5 comments about The Principle of Relativity (Dover Books on Physics).

1. Reading the original papers would be best, but if you don't read German then the Dover collection is the next best thing. In the paper on special relativity, the Lorentz transformations are derived via formulating and solving a first order pde, a treatment that no textbook presents (first order pdes aren't taught in math physics, in spite of the fact that every set of first order autonomous odes generates a first order pde). It took my teaching the subject to advanced undergrads in later years to realize what many others have by now noticed, namely, you don't need two postulates for special relativity. "Galilean invariance" is enough. The constancy of the speed of light follows from the requirement that there is no special reference frame.

   Einstein's presentation of GR is unsurpassed for conciseness and clarity, is a model for other researchers to follow when writing papers. Here, he introduces the famous misconception (corrected today in the better texts like Misner, Thorne, and Wheeler) that general covariance is a physical principle. Well, even the greatest minds make mistakes.

   Feynman wrote well, but no scientist to date has written better than Einstein.




2. One of the truly amazing things about the Special Theory is that you only need a decent grasp of high school mathematics and science to fully understand the two original papers. (Depending on your high school you may need to brush up on partial derivatives, but that's all.)
   
   The General Theory is something else again, but by reading around the equations and accepting the descriptions of what is being solved you can still gain some incredible insights into a great intellectual achievement.



3. Dover must be commended for re-printing this collection of 'seminal' papers which cover the development of Relativity. This collection includes Lorentz's papers "Michelson's Interference Experiment" & "Electromagnetic Phenomena ..." and Minkowski's "Space and Time". The latter was instrumental in forging the notion of Minkowski 'space' - and forever altered our conception of how we view time vis-a-vis space. Additional notes by Sommerfield are present as an appendix to Minkowski's paper.
   
   All this is in addition to the famous papers by Einstein which gave birth to Special & General Relativity. In particular, "The Foundation of the General Theory of Relativity" is, of course, a classic - but a tough read. The paper on Special Relativity, "On the Electrodynamics of Moving Bodies", on the other hand, is easily accesible to anyone acquainted with high school mathematics.
   
   Even for the non-physicist, with a suitable grounding in the requisite mathematics, this book is a real gem. In general, it serves an excellent companion to Einstein's The Meaning of Relativity, Fifth Edition: Including the Relativistic Theory of the Non-Symmetric Field (Princeton Science Library) and makes for a priceless addition to a personal library.



4. This book presents Einstein's orginal papers on relativity along with many other "classics" on the subject. A good understanding of college math and physics is a must.



5. I'm not happy with this book at all. I'm not a scientist outside of the field of information technology and I want something to explain Einstein's theories that I could read. I read such a book when I was young. It's out of print, but you can purchase it on Amazon used. It's entitled "Relativity: The Special and the General Theory--A Clear Explanation that Anyone Can Understand" by Albert Einstein.
   
   That did it for me, this book put me to sleep.

5 comments about General Relativity.

1. I used this text for a course after taking an undergraduate GR course based on Shutz. I found Shutz to be a much clearer and pedagogical text, and don't think I would have learned GR as easily if I had started with Wald. I think one requires greater mathematical preparation than I possess to fully appreciate the discussions involving topology in the second chapter and appendix. Oddly, however, this text becomes clearer as the reader advances through it: later chapters were more straightforward and still concise.



2. For about twenty years this book has more or less been a standard text that almost anyone seeking a deep understanding of general relativity should master. There is a good reason for that, it's a great book.
   
   The first half of the book covers the basics of general relativity. The approach is very geometrical, this is essential for a deep understanding of general relativity and to understand almost any of the literature. However, there is a practical issue with a geometric approach, the notation used in some books is such that it's very difficult for a reader to write the equations down on a piece of paper. For example, how can someone write an equation and make the symbols bold? Abstract index notation is used throughout this book. I think that is a great choice allowing one to write the equations using paper and a pen, but without sacrificing anything from the geometrical perspective.
   
   The book opens with a short chapter on special relativity, obviously it's not a very comprehensive treatment, but rather it's intended to establish notation and a point of view. After this there is a two chapter introduction to differential geometry. This material is needed for even the most basic concepts of general relativity. Some of the more advanced concepts of general relativity, e.g. causal structure, require knowledge of topology. Topology is treated in one of the very useful appendices. Wald's treatment of differential geometry and topology is excellent if you already have a fairly good grasp of these subjects, perhaps not so much if it's the first time you've seen them. I'd suggest readers uninitiated in these topics read a more basic introduction while, or before, reading this book.
   
   The rest of the first part consists of developing Einstein's equation, some cosmological solutions and the Schwarzschild solution. These topics are covered in virtually all general relativity books, however the treatment here is especially superb.
   
   The second part of the book consists of the advanced topics, as much as I liked the first part in my opinion it's the second part of the book that really makes Wald's book stand out. In brief the contents are: more systematic methods used for solving Einstein's equation (these are mostly centered on using symmetry), causal structure of space-time (an essential topic for many aspects of general relativity), the initial value problem, asymptotic flatness, black holes, spinors and quantum effects.
   
   These are all very well done, up to the standard established in the first part of the book. I especially appreciated the chapters on asymptotic flatness and spinors since these topics seem to be included in text books less frequently than the others. The quantum effects chapter also stood out. It covered a wide range of interesting topics (although some of them only briefly): semiclassical gravity, general issues in quantum gravity, non-renormalizability of the covariant perturbative approach, twistors (!), quantum field theory in curved space-time and of course black hole thermodynamics.
   
   Does it have any weaknesses? One could argue that it would be nice to see more material on experimental confirmation of general relativity. However, I thought the amount of material on this was fine. It might not be the ideal first book on general relativity, without an exceptional instructor many students seeing the subject for the first time might find the pace a little fast.
   
   To summarize, I think this is a great book, it's my favorite book on gravity. I consider it virtually required reading for an advanced understanding of general relativity. However, I would suggest supplementary texts be used for differential geometry and topology.



3. The book starts out well and then quickly becomes a refresher in topology! Not a great first text on general relativity if your higher math is shakey but as it progresses it becomes easier to read. Stable, concise, an exceptional work full of wonderful graphs, equations, and description.
   
   Not for the beginner or the merely curious, this is a book for the serious student pursuing relativity in context of astrophysics, cosmology, or some similar discipline.



4. Wald's book stands out as the clearest presentation of general relativity yet produced. The downside is that the conciseness often makes it inaccessible to the beginner. If you try to learn from this book, you *need to do exercises* (from this book or another). It is too hard to follow if you don't have the experience of computations under your belt. But once you do get to the point where you follow Wald, you will follow him easily and pleasurably, as he writes with effortless clarity.
   
   A common myth is that this book is overly mathematical. On the contrary--some of the highlights are where Wald discusses the role of Mach's principle in Einstein's formulation of the theory, and the role of our "philosophical projudices" in our choice of cosmology. Wald's talent is the ability to state the interesting physical or philosophical stuff without having to ramble on like other authors.



5. Wald's book was the standard text for two graduate courses in GR that I took during my PhD (one was an introductory grad course on GR and the other was an advance special topics course on black holes). The first six chapters lay the groundwork for classical GR, starting with a quick recap of the tensor notation (Wald's Index free notation is very useful), a little bit of differential geometry and the Einstien's equations. The Initial value problem of GR is treated in an elegant chapter that concludes the introduction. Advanced topics like black holes, area theorems, singularity theorems etc are treated in latter chapters, along with a nice chapter on QFT in curved space-time and the Hawking effect. I found Wald's book most useful for understanding the singularity theorems, which have been discussed very lucidly without sacrificing much rigor (some of the more technical details are best left to Hawking and Ellis).
   
   There is a priceless discussion on Penrose diagrams, asymptotic infinity, ADM energy and the BMS group which to my knowledge have never appeared in another book (one has to go back to papers of Ashtekar and Penrose to find this information).
   
   I had no prior exposure to differential geometry when I started reading the book (indeed my background at this point was an undergrad degree in Electronics, so my knowledge of physics when I took this course was rudimentary to say the least). I however found no difficulty in following this book, and indeed this book was the most exciting grad level book that I read until Polchinski's two tomes on String Theory. I would recommend Wald's book for anyone who likes to understand General Relativity and especially Black Hole Thermodynamics...and last but not least, the exercises in the book are all interesting and in some cases are pretty nontrivial. I learnt a lot of GR working out these exercises and highly recommend them to anybody studying this book...it is definitely worth spending time on these exercises.

2 comments about A Stubbornly Persistent Illusion: The Essential Scientific Works of Albert Einstein.

1. The most highly celebrated and recognized scientist alive today, Stephen Hawking has assembled, in this volume, highlights of Einstein's groundbreaking scientific works, such as his Special Theory of Relativity (1905) and his General Theory of Relativity (1915).
   
   Also included are Einstein's thoughtful views on politics, religion, the history and development of physics, and the interplay between science and the world.
   
   In a chapter titled "Selections from Out of My Later Years," Hawking discusses Einstein's reservations concerning quantum mechanics: "Einstein pointed out that if we were able to investigate microscopic phenomena on the smallest scales, we would be able to find deterministic relations." In other words, Einstein had serious doubts about the validity of Heisenberg's Uncertainty Principle, and rejected the fundamentally probabilistic nature of reality espoused by those who held to the workings of chance and randomness at the quantum (microscopic) level. "God does not play dice with the universe," he famously opined; "God is subtle but he is not malicious." He held adamantly (some would say stubbornly) to his belief that physical reality is, at bottom, deterministic.
   
   Hawking gives brief introductions to each of Einstein's papers, thereby providing helpful historical and scientific perspectives.
   
   Einstein once said, "Do not worry about your difficulties in mathematics. I can assure you mine are still greater." Yeah, right! Einstein is much too modest.
   
   In a sense, however, Einstein is correct. Although this volume is replete with mathematical equations, one can read between the lines and gain an improved understanding of his revolutionary theories of spacetime and gravitation.
   
   Einstein makes us smile with his wry humor: "Today I am described in Germany as a 'German savant,' and in England as a 'Swiss Jew.' Should it ever be my fate to be represetned as a bete noire, I should, on the contrary, become a 'Swiss Jew' for the Germans and a 'German savant' for the English."
   
   The book's title of comes from another Einstein quote, "People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion."



2. A Brief History of TimeGeorge's Secret Key to the UniverseArchimedes to Hawking: Laws of Science and the Great Minds Behind ThemEinstein: His Life and Universe
   
   Imagine where we would be if these two, Einstein and Hawking, had worked together!
   Hawking puts information into the theories and makes for a more complete understanding into Einstein's times and mind.
   A very good book, well versed and full of information, layed out and explained in their own words.

2 comments about Six Ideas That Shaped Physics: Unit R - Laws of Physics are Frame-Independent.

1. After finishing the first half of an advanced first year physics class, I was hopelessly confused with the subject of relativity as it had been presented by my teacher and by my text book. A few months later, I borrowed this book from my father and read it in about a week. When I was done with the book, I was amazed that I had ever been confused with such a simple and beautiful subject as relativity.
   The author skillfully anticipates many possible misconceptions and clearly explains the correct principles. The book at times can be tedious, but only when reinforcement of fundamental ideas is necessary.
   I've never read a physics book as good as this one.



2. This is a very good intro to special relativity. The author uses spacetime diagrams very skillfuly and explains even confusing topics very clearly. Overall, a very good book.

4 comments about Introduction to Tensor Calculus, Relativity and Cosmology.

1. There are many books on General Relativity but the reader has to be careful to pick the right one so as not to waste his (or rarely her) time and money! Lawden's book belongs to the class of technical introductions - it requires you to have an undergraduate background in physics and mathematics. The author is primarily a teacher and he has taken care to make the material as easy to understand as possible. On the other hand, this book will not enable you to go directly to the research literature. A great plus of the book is the very reasonable price. I have had the infuriating experience of paying more than $100 for a highly praised textbook only to find it unreadable. The mathematical formalism Lawden employs (tensor calculus based on covariant and contravariant tensors) is now considered old fashioned but it is still the easiest for a beginner in my opinion. Once you have finished this book, I recommend that you read Synge and Schild's "Tensor Calculus" for more depth in the mathematics and also "The Principle of Relativity" (a collection of original papers by Einstein and others) to get a feeling for the history of the subject. Both of these are also Dover paperbacks and very cheap. Then if you want a more modern approach, I recommend Schutz's "A First Course in General Relativity" which is still reasonably priced and will bring you closer to the level of contemporary research. Schutz uses a formalism of tensor calculus which aligns it with differential geometry and is now used in advanced textbooks.



2. This book is very good for those seeking an introduction to Tensor Calculus, Relativity and Cosmology. Nothing more than a basic and fundamental know-how of physics is required, atleast for the first few chapters. If you're comfortable with the simple basics of linear algebra, classical mechanics, electromagnetics and calculus, you should have no problem with this book.
   
   The book starts out with a basic review of classical physics and very quickly progresses to the Lorentz Transformation, and then to Cartesian Tensors and Special Relativity. Lawden handles the flow quite well, and covers the basic Special Relativity mechanics & electrodynamics as well as general Tensor Calculus & Riemann Spaces. Finally, he proceeds to discuss the General Theory of Relativity with a strong focus on Black Holes & Gravitational waves and analyzes elements of Cosmology in the light of the General Theory of Relativity.
   
   However, I would not recommend this book in and of itself for learning Tensor Calculus. Unfortunately, Lawden does not have any relevant references to Quantum Mechanics, either, which would have proven to be immensely useful to the novice reader. You'd also do well to brush up on your physics fundamentals before jumping head-on.
   
   This book primarily acts as a very basic introduction to those that are not familiar with some aspects of elementary modern physics such as Tensor Calculus and Relativity, and does an extremely good job of that.
   
   Personally, I'd highly recommend this book if you're looking to read up on Relativity & related areas.



3. I'm really impressed with the clarity of the material.
   I've worked through 21 problems in chapter 2, and the answers to the exercies do not have a single mistake in them yet.
   
   The publisher will also email you a .pdf file of all of the chapter problems worked out in detail. I've found the solutions to the problems to be a good supplement to the text itself.
   
   I would buy other titles from this author and publisher.



4. I have bought a bunch of books on Tensors, and in this one you actually get to do calculations, its the only one I have found of this sort. I am in the process of reading this book, but so far its a five star. I also looked up Lawden on the Internet and he was involved in a lot of early space research and was sought after by alot of companies, a must book for anyone serious in research. One last note, you need to get the answers for the questions to see techniques of his style.

5 comments about Relativity Demystified.

1. I've purchased a whole book shelf of the Demystified series, though I've only just started using them. As a former physics undergrad, these books at least *appear* to offer a level of treatment that I can handle as I wade back into the subject. The one I've been using the most is Differential Equations Demystified, and I've found that very helpful so far.
   
   *This* book, however -- General Relativity Demystified -- proved somewhat of a disappointment. Basically, before you can get into the physics, you have to get some handle on the mathematics of Tensors, which is covered in the early chapters, but I simply found the treatment opaque. I'm planning to get some other books on Tensors and study them carefully. Then I plan to return to this book, and see if the later parts of the book -- which deal with the physics -- prove to be accessible, once I have the tensor math down.
   
   Possibly, if the author rewrote the early part of the book to clarify the tensor discussion, he might still have a hit here. As I say, though, other books in the series look pretty good, and I'm very happy with the DfEQ Demystified book, which I've really been working my way through and learning something in the process.



2. This book covered a lot of the practical topics in GR. The writing is quite easy to understand. In some places, it seems to be too short. For example, the explanation of the basis in coordinate basis is not very clear. [Just refer to Carroll] However, be careful if you are the first time study in GR. You should get one of the other standard books, like Schutz, Weinberg, MTW(Misner, Thorne, Wheeler) otherwise, you will not be able to move too far in this area. Also, I really hope the editor/author can do a bit more thorough job in proof reading before releasing the book. There are many places where you could find sign errors or the indices placement are not correct. For example, the definition of Christoffel Sympbol in terms of metric and also the definition of symmetrization and also the -ve sign in the proper time definition....If you already know about the subject matter, this is not a bad reference book, just a bit tiring in keeping track of these minor errors.



3. While this is not exactly the "learning of relativity at the speed of light" the book advertises, unlike many others of the Demystified series, this volume does indeed have its high points.
   
   The lead up to Einstein's Field Equations -- although the notational gymnastics and some of the mathematics was daunting -- is nevertheless first class. It gives the reader a very much-needed window into the role the Linear Algebra notion of mathematical mappings and transformations -- especially as viewed from the point of view of "basis vectors," through "one forms," and on to "partial derivatives of Tensor Calculus" -- play in bootstrapping one's way up from the local Newtonian/Euclidian frame of reference to the more generalized space-time Reimann/Malinowsky frame. And most importantly, it shows by carefully selected examples and exercises how tensor calculus takes over from Linear Algebra in moving from the more local Newtonian/Euclidian frame to the more generalized space-time frame.
   
   In fact, reading between the lines of the book, one could argue that the whole of understanding the mechanics of relativity is grasping fully this single concept: of how to move mathematically from reference frame to reference frame -- that is, from inertial frames moving relative to one another in the Euclidian world to doing the same in the Space-time world.
   
   Doing this is not easy either conceptually or mathematically but is a necessity for getting from Newtonian to Einsteinian physics. If the reader learns to appreciate that the heavy-duty mathematics is required only for this task, and only in this light, then the ride will be infinitely easier.
   
   Even in Taylor and Wheeler's very down to earth treatment of relativity (in their "Spacetime Physics"), this kind of understanding is left in the background for the reader to infer and to ferret out on his own. A great deal of time is save in the earlier chapters of this volume by forcing the reader to understand early on why working ones way gradually up the ladder to the tensor Calculus is necessary: so that he is better able do all of the mathematical heavy-lifting seamlessly, later.
   
   One word of caution to the reader, which also is my only serious criticism of the book: The written dialogue is painfully sparse, so every word must be read carefully, weighed and parsed for its full meaning. It is helpful to read the book three times: First as an overview to see where the author is headed; and then a second time to understand the mathematical content -- especially the dizzy array of notations -- and then finally to put all the pieces together. That is, read it a third time just to confirm that one understands fully how the larger concepts match up with the corresponding mathematics.
   
   It seems much easier for the authors of physics and mathematical texts to roll out reams of equations than to give just the minimal explanations about how these equations relate to the underlying concepts they are supposed to explain and describe. Why leave such important connections to the reader?
   
   Realizing that this is not a book of prose, still it would be helpful sometimes to give ample and clearly written explanations, with even (god forbid), a little repetition from time to time, just as a guide so that the reader can confirm that he is making the correct interpretations along the way.
   
   Anyway, I am hooked on the Demystified Series and hope this book will be great preparation for the upcoming Demystified volume on String Theory.
   
   Four Stars



4. "Learn Relativity at the Speed of Light" is found on the back cover of this book and I think it's true. It was aproximately 1.23 light years ago when I first purchased this book and I am now on page 208(out of 328 total). My point is that the book is very good but to get through it requires a lot of work; relative to the math and physics background that you possess. I was totally stumped on pages 2 and 3 (Maxwells current-magnetic field equation). It will help to supplement this study with a book on tensor calculus and another relativity book by Hartle or Schutz. The worked examples and chapter quizes were great though and worth the effort.



5. This book is mathematically daunting. It covers the essentials and formulas of Einstein's theories through hundreds of worked (mathematical) examples. Unlike other books of the Demystified Series, I reckon this one not entertaining at all. It is absolutely not for beginners!

5 comments about Spacetime Physics.

1. Special Relativity (SR) is one of those subjects that require much thinking for maturating of ideas. I doubt even if many physicists really understand it. Of the many books written on this subject, Taylor and Wheeler's blink as a jewel. I believe it has many advantages over most of other books. It is extremely slow paced, but not to the point of being tiresome (the reason for this will be explained below). Most texts of SR start with a lenghty "philosophical" or historical discussion, then get to the maths of it, but in such a way that one has the impression that something is not fitting into the whole structure. The reason for this is, I believe, that SR is much needed in modern theoretical and experimental physics, but most of its intricate details can be left over. In other words, physicists need SR as a tool, but do not, as a general rule, need to think over it. Taylor and Wheeler's book is different. They know what is important, get directly to it (and this explains why, although being slow paced, is not tiresome), and fight the nuts and bolts of explaining in the most clear way up to date. You finish with the impression that you understood it. Good pedagogic machinery include questions and answers all over the book (some questions even somewhat silly, but who never thought about any of them before?), so you really feel that the writers are helping you and, most important, that they cared to write an understandable text. The book itself is appealing, appealing as most physics books are not, with a lot of pictures, boxes and quotes interspeded along the text. It is very pleasant reading, has every important information you need for SR as a working physicist (except the covariant formulation of electrodynamics, but this is not important as most of electrodynamical books treat this topic with all needed details, and the presentation of such a topic would find terrible difficulties for the organization of the text) and, most important, you will enjoy it and be able to read every page. One last note on the exercises. I thing nothing can be more educative for understanding SR than exercises like the ones you find there. They are not mathematically difficult, but as a general rule oblige you to think "four-dimensionally". They are the greatest fun of the book, and will make you really understand the meaning of SR. At this point, I must quote "Wheeler's first moral principle": "Do not make a calculation until you know the answer". This is the theme for all those exercises and, indeed, a moral principle that most physicists should follow - think about Feynman!



2. is the exercises.
   
   If you work through all (or nearly all) the exercises, you will have confronted most of the conceptual paradoxes that have come up in the discussion on Special Relativity since 1905. You will not only have mathematical explanations for them, but will be able to explain them in an intuitive way.
   
   (By "intuitive" I do not mean that they explanation will accord with Newtonian physics -- it can't, as they often give different results. What I mean is that you will be able to reason out the way things will turn out without always having to do the algebra.)
   
   On the other hand, if you just read through the text, the coverage might seem unnecessarily wordy and long. One will only find this discussion useful if you are really wrestling with the material, and trying to understand the apparent paradoxes.
   
   Perhaps this explains why there seems to be a "hate it"/"love it" dichotomy among the reviewers of this book. However, those who are tempted to dismiss it as merely wordy should keep in mind that the principal author is John Wheeler, whom Richard Feynman regarded as having incredible physical insight. (Wheeler was Feynman's thesis adviser.)



3. The aim of this book is to explain to one the essential of the theory of special relativity: The GEOMETRY of spacetime! Keyword: GEOMETRY. Those who give this book one or two stars because they think this book is too wordy or does not retain enough rigor simply do not see the simplicity and elegance in the authors' presentation.
   Yes. You don't see complicated equations in this book because the ideas are, as I said, geometric. The authors even tell the reader not to pay too much attention to things like the Lorentz transformation because it conceals the intuitive geometric ideas. Everything in speical relativity can be done without appealing to any local coordinate frames because spacetime IS geometry, the quantities we are interested in are inheritedly covariant. This is all built into the theory of relavity.
   And the paradoxes that arise when one first studies the subject can all be expalined by the relativity of simultaneity, which is again because space or time alone is not covariant but spacetime as a whole.
   This book gives a concrete meaning to spacetime. Things like 4-vectors are not just something the physicists cook up to make their equations look better on paper; They have their very own existence.
   As for the nontechnical language used in the book, I would have to say that any bright high school students can learn from this book.



4. A must for everyone who really wants to penetrate the mysteries of Einstein's special relativity. In my opinion the principal merit of the book is an special emphasis on the intuitive space-time concept with a very simplified mathematical presentation, all without lessening the subject. Few maths needed. Generously illustrated ! Many conceptual questions make one think hard. Also many problems with solutions( Odd numbers only ). One ends with a firm grasp on special relativity. A very amazing book !!



5. A fine introduction to the theory of Special Relativity using good visual descriptions along with clear understandable explanations and examples on a complex paradoxical subject. The writer appears to make a good effort to describe the concepts of the Special Relativity theory in a more descriptive, non mathematical way so that the concepts could be pictured in the mind geometrically more-so then mathematically, although he does use algebra and trigonometry to explain the fundamental concepts. But his use of algebra is only used sparingly to back up his more detailed geometric and visual presentations. His use of the term `free float frame' instead of using the terms 'inertial' or 'Lorentz' reference frames (of reference) is one example of how his descriptions are geared towards a more visual and even kinaesthetic perspective rather then a mathematical one, a perspective that I particularly like since I much prefer to understand Einstein's theories in a more fundamental picturesque way considering the fact that I have forgotten much of the mathematics that I learned in school years ago. I also found this style of presentation to be very helpful when the book explained the relation between event intervals (timelike, spacelike, lightlike) and the relativity of simultaneity.
   
   The book sums up relativity very well in the inside dust jacket:
   
   "Spacetime grips mass telling it how to move, and mass grips spacetime telling it how to curve"

5 comments about Elementary Particles and the Laws of Physics: The 1986 Dirac Memorial Lectures.

1. Feynman yet again gives great insight into the laws of physics, this time exploring the reasons for existence of anti-particles, starting from the dirac equation etc.. Plus some really outstanding photographs, that fella Weinberg will be chuffed to have his name mentioned on the book cover!



2. As usual, the best physics books are short and to the point, as is this one. The two Dirac lectures may serve as a perfectly good mini physics course all by themselves. I always enjoy a Feynman lecture, and this is no exception. He cuts to the chase without sacrificing the plot. But, I must say, in this case the Wienberg lecture is the better of the two. Weinberg's style has a particular grace & beauty about it that gently exposes the aesthetic meaning of the search for a picture of nature.



3. This short book, Elementary Particles and the Laws of Physics, offers two lectures: Richard Feynman's The Reason for Antiparticles and Steven Weinberg's Toward the Final Laws of Physics. These two talks comprise the 1986 Dirac Memorial lectures at Cambridge University. Both presentations are cogently structured and make fascinating reading.
   
   The talks were directed at an advanced audience, one that was familiar with quantum mechanics. Unlike many popular presentations by Feynman and Weinberg, these lectures are not suitable for the general layman.
   
   However, these lectures are accessible to a persistent (perhaps, stubborn) layman with a calculus background and a deep interest in particle physics. I am not a physicist, but I did take my share of physics, chemistry, and math courses several decades ago. I encountered Schrodinger's equation in more than one class, but not relativistic quantum mechanics. However, having recently read Bruce Schumm's wonderful review of particle physics (titled Deep Down Things), I was sufficiently motivated to work my way through both Dirac memorial lectures.
   
   Richard Feynman's lecture, The Reason for Antiparticles, is decidedly the more difficult. Feynman first demonstrates that quantum mechanics and relativity together require the existence of antiparticles, and then shows that they also establish the spin-statistics connection. Within a few pages advanced mathematical expressions appear and then persistently stay in the foreground for nearly the entire talk.
   
   Although understanding Feynman's mathematics is critical for a full and deep appreciation of his exposition, with careful, repeated readings the stubborn layman will have sudden moments of enlightenment and can come away with a deeper understanding of antiparticles and spin statistics. For readers engaged in some self-tutorial readings, it may prove helpful to return occasionally to this classic Feynman lecture to qualitatively measure progress. I have no doubt that, on a deeper level, Feynman's lecture will similarly challenge and enlighten physics majors as well.
   
   Steven Weinberg discusses his speculations on the shape of a final underlying theory of particle physics. Initially, his talk is deceptively easy as few mathematical expressions are used. However, about midway a Lagrangian density equation appears, ratcheting the difficulty several notches, as Weinberg considers a theoretical framework based on quantum mechanics and a few symmetry principles, that is also mathematically consistent with the Lagrangian dynamical principle. After discussion of some limitations of the Standard Model, Weinberg concludes his talk with a somewhat mathematical introduction to string theory.



4. From Richard Feynman, with love. Need more to be said? Read it, and read it again. This one can be read all over again once in a while and does not get boring.



5. When I readThe Feynman Lectures on Physics including Feynman's Tips on Physics: The Definitive and Extended Edition, I was hoping to understand the reasoning behind the exclusion principle, and was disappointed to find that RPF felt that this was too complex for undergraduates, so he asked them to take it on faith for the moment.
   
   Here he is talking to a more advanced audience, and explains it - he was right, it's tough. I'm still struggling to understand it, but I have confidence that this is a good book to help.
   
   [Added nearly a year later] Having reread the book several times, I finally understand Feynman's lecture! As is often the case, once I understand the principle, I see relationships to various other things I had not fully understood before.
   
   I should also comment on Weinberg's lecture: he's talking about more speculative areas than Feynman, which is perhaps one reason I found him less enlightening than Feynman, but in a rather vague way I follow what he's saying. Certainly these are fascinating ideas, but they don't sing to me like Feynman's lecture.

5 comments about Special Relativity (M.I.T. Introductory Physics Series).

1. This book was extremely helpful when I was taking a class on special relativity. The author introduces new concepts and rules in a very logical order, and the examples clearly illustrate the material. The book is written very clearly, especially for such a complicated subject. The problems in the back of every chapter allow you to test yourself and make sure you have grasped the material, since some of them have answers in the back of the book. Overall, a great book to either teach special relativity to yourself, or as a companion for a special relativity class.



2. If you are looking for the fastest way to learn and use special relativity (this is not about general relativity as the previous reviewer says), this is not the best book to use.

   After an introductory chapter 1, which quickly previews much of the later material, French systematically analyzes the many observations and contradictions (the Michelson-Morley experiment just one of them), astronomical and laboratory, about the behavior of light that fitted neither an ether-wave model or a particle model. We are thus lead to a deeper appreciation for Einstein's insight and genius in his creation of the special theory of relativity; it was much more than just an extension of the Lorentz-transformations.

   French is a master at his subject, and his systematic elucidation will reward the reader with a deep understanding. His problems are very well designed, and he provides answers which is always very helpful in learning.

   If you have some time, and would like also to gain historical perspective about what it was like to struggle for a consistent theory in a mass of contradictory observations from the world view of Newtonian mechanics, I highly recommend this book.




3. "Special relativity" is discussed in many classical mechanics, electromagnetism and quantum / modern physics textbooks. You may learn different aspects of this subject from these books.
   
   This book is specifically designed and written for those who want to learn special relativity comprehensively from one single source.
   
   The book starts with the basics of the theories behind special relativity with simple arguments and plain language. In the first 5 chapters, you learn the mechanical fundamentals of special relativity. The examples and end-of-chapter problems are very useful and instructive. Furthermore, the answers to all problems are given in back of the book as well, which enables you to check your answers. Starting from chapter 6, more advanced topics are introduced, like momentum, energy, basic electromagnetism and so forth. Again, the problems should be solved by students in order to gain a thorough comprehension of the subject matter. The diagrams and pictures in the book are also very helpful to understand the concepts.
   
   The bibliography at the end of the book can be used to consult for further discussions, because special relativity has many applications in various areas of physics.
   
   To sum up, this book, all by itself, can be used to learn and understand special relativity very well in a short period of time, because it is concise, simple, effective, pedagogically well-prepared and very suitable for self-study. You do not need any other fancy, expensive book. A.P. French does an excellent job in laying out the principles of special relativity with illustrative examples and problems. It deserves every penny you paid.



4. I purchased this classic work at MIT, circa 1972, and have referenced it too times to remember. When I bought it, the book was part of the M.I.T. INTRODUCTORY PHYSICS SERIES. It contains about everything one could wish for on the subject matter. The derived transformations for acceleration and force (i.e. of d(mv)/dt) have been especially useful, and are not often included in other books. It is truly a gem, created by a world class physics instructor at the top of his game. G.R.Dixon.



5. This book was in good condition, and is very easy to follow. Recommended for anyone wanting to learn university level modern physics but not wanting to go cross-eyed or get lost!

5 comments about About Time: Einstein's Unfinished Revolution.

1. About Time discusses twentieth century developments in theoretical physics and their impact on our notion of time. Davies is a well known and prolific Australian science writer. I offer the following thoughts for potential readers.
   
   Aimed at the general reader the book does not require a detailed knowledge of physics or mathematics. In light of the counter intuitive nature of modern theoretical physics, however, the uninitiated reader may require a little effort to get the gist of this intriguing but esoteric topic. Given the broad scope of material addressed in the text the time spent on each issue is relatively limited.
   
   I concur with previous reviewers that the book is generally quite readable - Davies' technique of using a hypothetical skeptic as a means to highlight certain issues may strike some as awkward (that was my impression). From an overall stylistic perspective, however, Davies has improved significantly from his earlier efforts and become a solid writer.
   
   The author does a nice job of discussing relativity and some of its implications. For instance, his handling of the twins paradox is among the best I have come across. I agree with Davies that there is solid empirical evidence to support time dilation - his transition from this to a tenseless view of time, however, seems premature - or at least insufficiently argued. Indeed, many of Davies assumptions regarding the nature of time, though interesting, will likely not be convincing to those who do not hold his narrow verificationist view of knowledge.
   
   I found the latter part of the book that discusses highly speculative issues such as time travel to be of limited value. At this point much of the thought in this area, though wonderful to ponder, is largely unstructured and untestable - more science fiction than science. Probably the two biggest challenges facing About Time, however, is it dating (a lot has happened in the interim) and the increased competition in this genre of writing.
   
   Overall, it is not a bad book. There are, however, better options available to readers interested in this subject matter - Greene, Singh and Ferris are authors worth looking at.



2. After eight years in the waiting the CERN Hadron collider is set to resume testing in 2007. In so doing it will -- according to noted physicist Ed Witten -- have an opportunity to test some of the more gross predictions of cosmic string theory and in so doing perhaps re write notions of space and time itself.
   
   That being said, Professor Davies book is up to his usually high standards of scholarship and communication in discussing that most pivtol of topics: time.
   
   From recounting speculations of ancient philosophers such as Augustine to telling the modern story of how we are better understanding time to his own speculations, Davies does a wonderful job of briefly recounting the material and making it accessible to the layman.
   
   Well worth reading, but definately keep your eyes peeled for events at CERN.



3. This over-simplistic physics account which holds that universal time and entropy are reversible and that Poincare's recurrence theorem disproves the 2nd law of entropy increase in isolated systems (and Boltzman's statistical mechanics) ignores the fact that physics equations are idealizations and that mathematical equations are tautoligies that do not define direction or cause. These arguments generally ignore real world effects such as friction, noise, chaos (e.g. the 'many body' problem for gravity) and non-linear effects and correlations etc.
   
   For instance the wikipedia description of Poincare's recurrence theorem points out that environmental noise and chaos alone can break the idealization. In addition chaos can cause entropy increase in both time directions (e.g. P. Cipriani). Various authors (with articles on the net) have pointed out that for non-adiabatic processes, 'the natural evolution of entropy is towards larger values because the natural state of matter is at a positive temperature' (M. Campisi), and only in adiabatic classical mechanics are energy and entropy both conserved and time reversible (e.g. Silverberg and Widom). In addition 'One of the basic postulates of the classical statistical physics is an assumption that the particle's interaction range is considered to be small compared with the system size. If this condition does not hold the internal and free energies, entropy etc are no more additive physical quantities... the Boltzman relationship between the entropy and the statistical weight is not any longer valid. The non-extensive systems are common in physics- gravitational forces, Coulomb forces in globally charged systems, wave-particle interactions, magnets with dipolar interactions etc.' (Apostolov et al, April, 2007).
   
   Essentially all of Davies' book is concerned with the idealizations and so most of the paradoxes he describes are not real and he has not updated the debate since Boltzman from the early 20th century. His analysis of the 'twin paradox' from Einstein's early relativity of the same era is also dated (even though his book is a century later!). This paradox about the twins each measuring each other's clocks with telescopes appearing slower to the other when one takes a fast spaceship into space and yet one returning younger is readily dismissed by Davies as the effect of the traveller's acceleration, is in fact not fully accepted. For instance S. Kak's recent article succinctly describes the actual situation:
   
   "There exist many different 'resolutions' to the paradox [which] are not in consonance with each other. The slowing down of all clocks and processes - including atomic vibrations - on the travelling twin cannot be laid on the periods of accleration and turning around during the journey, since they can, in principle, be made as small as one desires... Einstein's own 'resolution' in 1918 (13 years after Davies says he reolved it!) which was an attempt to counter the criticism related to the paradox until that time, used the gravitational time dilation of the theory of general relativity to explain the asymmetrical time dilation of the travelling twin. This explanation is generally considered wrong and is different from the other 'resolutions...In this article we present a new principle for the identification of inertial frames in a matter-filled universe [assumed away in the other idealizations!] that allows us to easily resolve the twins paradox. The principle implies that the identification of a frame as being inertial depends on whether the universe has spatial isotropy with respect to it. This is equivalent to determining the motion of objects against the background of distant stars."
   
   One might describe this solution as 'Machian', whose central principle was that a particle's mass was determined by all of the other particles in the universe. There has been some evolution of this (Mach's general) theory which has gained some popularity and some authors have shown how it can be adapted to conform to any gravitational theory including Einstein's relativity. There are also some good books on this subject for sale on Amazon.
   
   So once again when one does away with the idealizations and enters some reality into the models one can resolve many of the so-called paradoxes.



4. This, as the title states, is a book about time; all the possible aspects of time, from that of the Greek philosophers, through Newton's idea of time, to Einstein's relativistic view of time and beyond. The book is a blend of philosophy, physics and physiology, but heaviest on the physics aspects of time. Everyone thinks that they know what time is, but on closer examination it is not so clear what time actually is. Is it an illusion or just the interval between events? Does it flow, or is it only perceived to do so? Does time always run forward, or can it run backwards? What is imaginary time, or quantum time? Did time start at the instant of the big bang? What does time look like in a black hole? How does the brain perceive time?
   
   To the ancient Greeks time was a mystery, to Newton time was absolute and to Einstein it is relative to the observer. All these are subjects (and much more) that are discussed in the book; discussed in a very literate and highly entertaining manner. This is not, however, a physics text, although much of it is concerned with the physics of time. There are no equations and only the results of relativity theory, quantum mechanics and cosmology are discussed, not the details. Nonetheless, it brings time to life (to use the sort of analogy that is discussed in the book) in a way that the details of a physics text cannot. I highly recommend this book to students and to anyone who wants their perception of the most basic aspect of consciousness challenged. Read this book and you will never perceive time in quite the same way again.



5. I liked this book. When I read the first pages, I thought that I had chosen the wrong book, but afterwards everything changed. Here you can find a light and clear review of many aspects of time.
   
   It is not perfect, and some times it is not clear what the author means with "time reversal", etc, even if he tries to explain it several times. The theory about the proximity of Doomsday is also quite weak.
   
   In spite of this, you find a clear view of time as it is currently known by science. I have not found many new ideas, but in general they are well structured and consolidates what you have read separately in many other books. Apart from that, it has good rhythm, and it is easy to read and understand.