The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory

Each chapter in this book lays down the foundation for the next chapter. Greene manages to group together scattered discoveries from the past century or so according to their relevance to the topic at hand, and it feels very natural. Every complex concept is explained in somewhat technical detail and then followed up immediately by a clever (and occasionally humorous) analogy. The key points are always restated and rephrased to make absolutely sure the reader is on the same page with the author. This method really does wonders for nailing important concepts to your head, which turns out to be absolutely essential as the book progresses and new ideas are stacked atop the old.

This book, overall, is interesting. There are some extraordinarily intriguing chapters that will have your mind racing for at least a couple days, trying to piece together the chapter's implications, and then there are a couple dull chapters that almost feel like a chore to get through. However, the dull chapters, which seem to be flooded with basic mathematical and technical details, are necessary to understand the big picture. Greene only presents us with the details we need to understand, nothing more, and I honestly can't think of a way he could have made these dull chapters exciting.

If you are a curious physics newbie, or only know bits and pieces about the basic concepts of string theory, special and general relativity, quantum mechanics, black holes, the big bang, or hidden dimensions, this book is certainly for you! If you are already knowledgeable in these subjects and seek the deepest technical and mathematical information about them, I'm guessing you will not find what you are looking for in this book.

By way of explaining the use of the term "layman," let me point out that this book is not light reading. I don't believe it can be read by those without at least some exposure to college level physics. I am a former high school physics teacher, and I had to really stretch to understand Dr. Greene's explanations. Nevertheless, considering the mathematical and physical complexity of the subject matter, Dr. Greene has done a splendid and remarkable job of explaining the subject at a conceptual, nonmathematical level. Anyone with a physics background through the level of an introductory course in modern physics will find Dr. Greene's treatise accessible. It brings the reader closer to the current state of research in the rapidly moving field of superstring theory than books written even two years ago.

The book requires work, but it was a labor of love. This book is beautifully and artfully written and was a joy to read. I recommend it highly to anyone with the modest physics background described above who enjoys exploring theoretical physics and cosmology at a level approximating that of Scientific American.

Some of the reviewers have faulted Professor Greene for communicating his ideas without using complicated mathematics. To me, this is one of strengths of this and other similar books that are written for the lay people. Those readers who are mathematical geniuses can find plenty of other resources to suit their taste. Others think that it is inappropriate to write about incomplete theories that cannot be experimentally verified at the present time. This is absurd. This is what the progress of science is all about. I thank Brian Greene for sharing his ideas so clearly with the rest of us. I am going to talk to my young daughter about this book in the hopes of inspiring her to someday join the minds who want to unlock the mysteries of our universe.

The Elegant Universe is worth the purchase price, if only for chapters 2,3 and 4 which lay out, in terms understandable by anyone, the ideas behind Einstein's theory of special relativity, Einstein's theory of general relativity and quantum mechanics. I highly recommend it for this purpose alone.

The rest of the book deals with the central connudrum of modern physics which is, unfortunately, although the theories of relativity (governing large systems) and quantum mechanics (governing minute systems) have been experimentally verified over the past century and are indeed true, they are *not compatible*. Greene does a good job of explaining why the theories are in conflict with one another.

The rest of the book deals with string theory, which Greene and a lot of other string theorists claim can "bridge the gap" between relativity and quantum mechanics. Although Greene does a terrific job of explaining string theory through graspable metaphors, towards the end end of the book, my tiny brain had difficulty understanding some of the concepts.

Yet, by far, Greene provides the most accessible description of this revolution in physics. Greene is quite obviously an ardent evangelist of string theory and his optimism concerning its possibilities lend a certain energy to the read, getting you through the difficult parts. You can tell that this is a man who loves and is excited by what he does for a living, and that excitement is contagious.

Anyone with an interest in why the universe is the way it is will be well rewarded by this text.

Greene's prose is clear, analytical, and well thought out. At least a half dozen times while reading the book, I said to myself, "Hmmm, but what about X?" to find a few paragraphs later Greene would write, "You may be wondering about X. Well, here's how that works..." To me, this is a sign of a clear thinker and helped make the book even more enjoyable to read. If you're at all interested in cutting edge physics theory, this is a great book to turn to.

As a reader I have more than a casual interest in modern physics and have read dozens of books in this vein, however I do not have a math background sufficient enough to deal with the professional literature in the field. I have found this work one of the best in explaining string theory. Mr. Greene's approach of using analogy and metaphor is right on target. His sometimes humorous approach was a good antidote for what could become overbearingly theoretical.

The first half went down pretty easily in spite of the difficult nature of the subject. Brian Greene deserves much applause for pulling off this bit of magic. The second half gets tangled up in the author's own areas of research and I felt that he suddenly began talking to a different audience, in this case his peers, and instead of an explanatory tone, the book seemed a little bit argumentative. Of course this is a topic where anything said in a definitive manner is likely to provoke a professional argument. Nonetheless, the first half of the book is well worth the read and more than adequately covers the field for the reader where this topic would be of interest. The second half will be of interest to folks with more background.

This book is well written, the examples are understandable and do give you a flavor of superstring theory, they explain the difficulties of conventional quantum field theory that superstring theory is able to resolve. There are no equations in the book.

This is all great however I must say that at the end of the book, I got the feeling that I have no real understanding for the theory unless I take for granted what the writer claims to be true. Have to take it in on faith. Having said this, one should not expect to be able to argue superstring theory with the scientists in the area after reading a popular science book.

I rate the book with 5 stars; it is an amazing achievement over what was available in the field before this book; it is no small feat to translate superstring theory from it native language, mathematics, to english.

After this well thought out primer, the second half of the book introduces us to the latest innovations in physics, namely string theory. He points out the reliance of this theory on some rather esoteric mathmatics, and as such, string theory is a bit more difficult to relate to. If one continues the walk, however, you will be introduced to such bizzare concepts as a ten dimensional universe, and two dimensional loops being the basis of all matter, defined only by their vibrations.

This is journey worth taking, though you may have to slow down to a crawl at times. In the end though, the universe won't ever seem quite the same.

How "accessible" is the book? Well, you don't need an advanced degree in theoretical physics in order to understand it. But a reader with no knowledge of college-level physics or mathematics will probably find it rough going. You probably should at least have an idea of what the subject of quantum mechanics is, as well as some notion of relativity - although Greene describes both of those subjects for the neophyte. You should know enough mathematics that the idea of nine or eleven-dimensional space doesn't blow you away completely. If the suggestions in this paragraph intimidate you, then I suggest reading the incomparable "One Two Three....Infinity" by George Gamow before reading this book. Despite being more than 40 years old (Gamow certainly had never heard of superstrings), that book will do a wonderful job of opening your mind to the point where you can accept the notions of "The Elegant Universe" more easily.

My only reservation about the book is that it seems premature. According to Greene's account, there is remarkably little direct physical evidence to support superstring theory. That is not to say that there is physical evidence CONTRADICTING string theory, either - there isn't. But when many of the best brains in the human race are devoting their lives to studying string theory, one might ask whether they are jumping the gun by giving so much effort to an unproven theory. There seem to be at least a couple of answers to that objection.

First, there are good reasons for the absence of physical evidence for string theory. One is that the physical events predicted by string theory can be experimentally discovered only under extremely high-energy or physically tiny conditions - conditions which we lack the technology to create and examine. Another reason is that string theory addresses such tiny, precise quantities that the usual "approximate" mathematics we use in everyday life is inapplicable. For example, a doctor wouldn't think twice about prescribing the same dosage of medication for a 150-lb. patient and a 155-lb. patient. Those weights are approximate anyway, and nothing would be gained by making a distinction. However, the quantities dealt with by string theory are so small and precise that the string theorists have not been able to confidently predict the outcomes of the experiments which would be performed to test string theory! A second answer is that there is a sort of "philosophy of science" which goes back centuries. That philosophy carries several assumptions, two of which are symmetry and economy. Symmetry means essentially that the laws of physics are the same everywhere and at every point in time. It means that no observer is special; that no person (and no galaxy!) can regard himself as the center of the universe, or the only object in the universe that is at rest. There is no proof of this principle, nor can there be, but using it as an assumption has led to many scientific and intellectual breakthroughs, including Einstein's theory of relativity. The "economy" principle means more or less that the universe contains nothing except those things necessary to make the universe work. Scientists have discovered 16 different varieties of basic matter particles and 4 "force" particles. But physicists are extremely reluctant to accept the idea that all 20 of those particles came into existence by themselves, for 20 independent reasons. Historically, science has made progress because scientists have explicitly rejected the notion that "things are as they are because they are that way".

String theory dominates theoretical physics because right now it's the "only game in town" which maintains economy and symmetry. It's the only theory we know of which gives hope of unifying what we know into one mathematically and logically consistent theory.

The book really belongs to the world of mathematics rather than physics. Rather than performing physical experiments and finding a pattern in the results, string theorists start from highly theoretical assumptions and then work out the theory of what would happen if those assumptions turned out to be true. This is what mathematicians do! Indeed, Greene relates one example of a physicist solving some complex mathematical problem by attacking it from a string theory point of view, when at the same time a mathematician was working on the same problem by employing much more difficult techniques. The mathematician and the physicist came up with very different answers, and to Greene's obvious satisfaction the physicist turned out to be right.

Rather than writing a physics textbook here, Greene has taken a contemporary-history approach. He covers the major discoveries chronologically, setting the stage for each new advance by lucidly describing the uncertainties and obstacles that were resolved by the next breakthrough. This approach gives the book more human interest than a textbook, and places each idea in an understandable context.

By the way, we can confidently dismiss the criticisms of a couple of reviewers below who claim that the book is scientifically false or unsound. Greene is a Rhodes scholar, a world-class researcher, and a professor at Cornell and Columbia. He knows what he's talking about.

But I must return to what really makes this a five-star book, which is the clarity of the writing and explaining. As a math teacher myself, I was deeply impressed by Greene's ability to communicate such advanced ideas to an audience of educated laypersons. I'll bet he is a great, great teacher.

String theory tells us that these fundamental particles are not really so fundamental after all. Instead, the vibrations of a tiny one-dimensional loop of string within define the physical properties of each of the fundamental "According to string theory, the properties of an elementary "particle" - its mass and its various force charges - are determined by the precise resonant pattern of vibrations that its internal string executes."

There are no known experimental circumstances in which the standard theory disagrees with experiments in quantum mechanics. Similarly, there is no known experimental circumstance in which the general theory of relativity conflicts with measurements in the cosmos. Yet scientists realize that these theories - successful as they are - cannot be complete because they are mutually inconsistent. Before superstring theory, however, all attempts to reconcile the general theory of relativity on a quantum scale have failed. This is the impetus for the search for the "theory of everything," or TOE, and it is the subject of Brian Greene's book.

Greene begins with a high-level summary of string theory, encapsulating the essential elements of the theory in the idea that the resonant patterns and energy of string filaments within define fundamental particles. He then outlines the problems between the general theory of relativity and quantum mechanics, which is the driving force behind the quest for a unified theory. In laying this foundation he gives crisp and clear descriptions of the ideas in relativity as they pertain to time and space - showing how Einstein turned our past notions of these things upside down.

Next, Greene describes quantum weirdness, and how quantum theory, like relativity, attacks our sensibilities and intuition. There are the usual discussions of the double-slit experiment along with a brief discussion of Feynman's formulation of quantum mechanics in which particles are viewed as traveling along every possible path through space and time and engaging in the weirdness of self-interference.

With the essential ideas in quantum physics and general relativity established, Greene shows how these theories - successful as they are - cannot be complete because each is incompatible with the other in its own sphere of influence. Greene then makes the critical case for string theory. Among his repertoire of evidence, the most commonly cited are aspects of symmetry and beauty. Unlike the standard theory, string theory does not dabble in tables of measured data, which are then incorporated into the theory. The standard model is impressive, but not until you first measure the charges and masses of the fundamental particles. String theory, on the other hand, is "unique and inflexible .... It requires no input beyond a single number ... [and] all properties of the microworld are within the realm of its explanatory power."

The real problem with the theory is that it is so mathematically intense that nobody can solve the theory's equations exactly. In fact, it's so difficult that only approximations for the equations are known - even the exact equations have proven elusive thus far. This makes it hard to press the case for superstring theory. Greene Signatures") devoted to physical evidence in support of the theory, but the evidence so far is pretty thin. Among the most encouraging results is the fact that superstring theory requires the graviton. In principle, superstring theory can be used to calculate the masses and electric charges of the fundamental particles, but so far the mathematics has proven intractable.

Much of the book deals with the mathematical issues that are blocking present progress (though in a strictly quantitative fashion - there are no equations). There are some good discussions about higher dimensions (superstring theory demands them) and the warping of space. I found the discussion of M-theory especially interesting. You see, there are several superstring theories, and M-theory explains how they are really all just different manifestations of the same.

About 2/3 of the book deals with historical backgrounds in general relativity, the standard model, and developments in superstring theory. I expected more subject matter on cosmology, but that's okay. The book is great as written. There is a chapter on black holes and how superstring theory helps us understand them better. There is also a chapter on cosmology and implications for superstring there. Among other things, superstring theory helps us deal with the problems of a mathematical singularity in the explanation of the big bang, but the jury is still out on superstring theory and singularities in black holes.

The book ends with a chapter on future prospects, and it has a very useful section containing endnotes for the various chapters (I highly recommend reading the endnotes). To top it off, there is a wonderfully useful index, and the figures are all nicely done (though I would have included more figures - that's my only complaint).

This is a wonderful book. It's written at an intelligent level, but does not burden the reader with the almost intractable mathematics of string theory. Greene has done a masterful job of explaining in clearly illuminated terms the ideas of what may be the most important theoretical study of the next century. If you enjoy intellectual stimulation and thoughts that will make your head swim, then this is a book you really must read.

Duwayne Anderson, February 03, 2000

The book begins with a very lucid explanation of Einstein's Special and General Theories of Relativity, then leads into Quantum Mechanics, and discusses the inconsistencies between these views of physics on a large scale (General Relativity) and physics on a very small scale (Quantum Mechanics). Dr. Greene then goes on to explain superstring theory and how this new framework smooths out many of the contradictions between General Relativity and Quantum Mechanics.

Using this new understanding of superstring theory, Dr. Greene leads the reader through a myriad of otherwise mind-boggling topics such as: the beginning of the Universe, the possible existence of other universes, 11-dimensional existence, time travel, tears in the fabric of space, and black holes. It's written on a level for the layperson (like me) and I think most people will be able to understand and appreciate all the concepts presented.

First, be warned that Dr. Greene provides rather distorted and misleading view of some important historical issues of modern physics. His narrative is strongly twisted to support his claims that strings are here as a "natural" answer and the only game in town. E.g., Planck's struggle with the black-body radiation, as depicted by Greene, is closer to a fairytail than historical and scientific truth.

The places where Greene touches statistical physics and thermodynamics are full of principally wrong statements which indicate that he has just a very superficial knowledge of these matters.

His exposition of Quantum Mechanics (QM) pushes favourable but false statements about quantum "weirdness", showing that he is evidently unaware about many classical and modern works showing QM from a rational and unparadoxical perspective (starting yet from von Neumann in 1927).

Greene's statements about a "fundamental" gap between QM and General Relativity (GR) are just other common mantras of the string army, indicating their superficial insight into these underlying theories. BTW, he is not indicating properly how the string concept offers a synthetizing cure.

His "review" of the 20-th century physics is not only biased but also tedious, repeating notoriously well-known (but too often one-sided and misleading) statements and fairytails about physics' celebrities.

As for the strings grandeur: I do not believe that there is too much hope that a rational Theory-of-Everything might be elaborated by people who exhibit so irrational views of quantum, relativistic and statistical physics, confuse distinctions between mathematics and physics, evidently do not understand probability theory and thermodynamics, etc. And of course, it is just funny to read on the same page that the M-theory is just IT, whilst still being unable to generate even basic equations, state its own principles, or even to demonstrate how standard physical equations or parameter values follow from IT.

Actually, there is still NO string theory at all: it is rather a big gulash of mathematical exotic adhockeries, of formalistic ambiguous escapes, everything scrambled with grand supporting statements of Muhammad Ali.

But most fundamentally: Greene, Witten, and the whole string army are pushing their philosophy that all kind of "weirdness" is just an intrinsic feature of our physical image. However, many rational physicists think that they are rather building a babel tower on sands, on the underlying theories they do not interpret rationally. I do not believe that the aim of the Theory of Everything ever was/is something of this kind. I am just sorry about so many laymen that are evidently so easily fooled by this new type of mysticism, combined with some lack of scientific modesty and honesty.

In summary, Greene's "Elegant Universe" is neither an elegant image of the universe, nor an adequate narrative of modern physics and its history.

Over the last half-century scientists have made great strides uncovering the mysteries of the universe. The universe has two foundational pillars: One is Einstein's theory of relativity, which provides a framework for under-standing the universe. The other is atoms and subatomic particles like elec-trons and quarks. But the two "big" and "small" theories don't fit together. The new superstring theory (referred to as "the string theory") puts these two structures together and comes up with a plausible explanation of all matter. This new hypothesis has, to date, withstood extensive testing.

Now, physicists have probed deeply into the structure of matter to show that everything in the universe, big and small, is some combination of quarks, electrons, or nutrinos. Did this occur by chance, divine choice, or is there a scientific explanation? We don't know, but the string theory comes closest yet.

It is possibly the "theory of everything" (TOE). It follows that if you understand everything about the ingredients of something, you understand everything. Now, we understand that if anything like the string theory is correct, our universe has properties that would have dazzled even Einstein. This new theory destroys old concepts. For example, it dictates that there is no time or distance. The feeling of space is in the eye of the beholder; it depends upon where you are and where somebody or something else is. But the "big bang" theory of the universe fits the string theory, which holds that the universe came to being from compressed energy the size of a grain of sand.

So it appears at last we have a unified theory of matter and force that makes up our universe. It derives from minute, oscillating pieces of string which, by the way, communicate with each other. And there is no time, nor space. Maybe our universe is merely a frothing bubble on a vast cosmic ocean aptly named "multi-universe." The author modestly concludes though: "As we (scientists) collectively scale the mountains of explanation, each generation climbs a little higher."

This imaginative, interpretive book is for those with a scientific turn of mind and a good feeling for math and physics. It offers a breathtaking view of our universe.

And so this year I chose "The Elegant Universe" as the next instalment of my quest to keep 'tuned-in' with physics and cosmology.

Different class, mate.

The first third of the book explains the current pillars of modern physics - Einsteins Special & General Relativity, Newton's Gravity, Quantum Physics, and the incompatibilities between them - and I have to say I learned more from those hundred pages than from Stephen Hawking's entire book. Brian Greene has what Hawking lacks - the ability to TEACH, not just tell.

I write speculative fiction as a hobby, and when I read a book such as this I tend to fold down the corners of pages which contain some interesting idea or other that I fancy turning into a story; I must have folded down every second page, such is Greene's verve for bringing home the wonder (and sometimes the absurdity) of nature's laws as we currently understand them.

The middle chunk of the book explains how String Theory could unite the inconsistencies of such laws, and Greene does a sterling job of explaining (to a semi-layman such as myself) the whats, hows, whens, wheres and whys.

And then we really got down to business; the last chunk delves into quantum geometry, the finer points of 'Calibi-Yau shapes' and other abstract concepts, and at this point I began to lose my grip on reality. Nevertheless, Greene has structured the book such that the reader can skip chapters that bore/confuse/both without losing the thread of the book entirely. And as such I made it to the end after all.

I'm no scientist or mathematician, just a bloke who's fascinated by physics and cosmology from an everyday standpoint and who has a thirst for knowledge. If you're the same, this book will quench it admirably.

Perhaps the greatest problem with this style is he presents the examples backward. Not explaining what Planck's constant is and how it is used and, once we've established the goal, moving on to the example, Greene instead starts with the example (metaphor, actually) and I have to read through the tedium of how the residents choose to divide rent responsibilities and only later discover which of the example's various parts actually apply.

In lieu of this book, I would recommend Michio Kaku's "Hyperspace" which, while not up-to-date on the latest, greatest discoveries like Greene (e.g., M-Theory), is much more direct and provides a great deal of interesting information as to how these theories were found. And the U.S. Treasury department doesn't appear even once.

First, although it describes the theory of superstrings and the evolution of the theory quite clearly, the author is such an enthusiast that he leaves the impression that superstring theory solves more problems in physics than it does. I agree with the view of Gerard t'Hooft (1999 Nobel Prize winner): "Imagine that I give you a chair while explaining that the legs are still missing, and that the seat, back and armrest will perhaps be delivered soon; whatever I did give you, can I still call it a chair?" Superstring theory is clearly onto something; in particular, it enables us to avoid some unjustifiable renormalizations that embarrass us in the "standard theory". But so far, it has essentially no testable consequences that would clearly distinguish between it and the standard model.

This lack of testable consequences doesn't discourage the author or other workers in superstring theory, and perhaps it shouldn't. But it's a symptom of the fact that most of the workers in superstring theory are better mathematicians than they are physicists. For example, Edward Witten, the guru of superstring theory, has won the Fields medal in mathematics, which is more exclusive than the Nobel prize in Physics, but so far as I can recall at the moment, nobody has won the Physics Nobel Prize for work on string theory or superstring theory.

Greene's book is an admirable explanation of why superstring theory was devised, and how it has progressed and is progessing. As such, it's well worth reading. But I have the extremely uncomfortable feeling that superstring theory will sooner or later have to be drastically modified, when someone with novel physical intuition or physical observational skill comes up with observational or experimental results that lead to a new idea, perhaps a very simple new idea, like the Heisenberg uncertainty principle or Special and General Relativity. (Heisenberg and Einstein were primarily physicists, not mathematicians.)

In particular, I will not feel comfortable with *any* approach to unified field theory until the Higgs particle has been unambiguously detected, and its mass measured fairly well. I think that will clarify the situation a great deal.

So, yes, if you are interested in modern physics at all, read this book. But as you read it, keep in mind that in trying to create a "Theory of Everything", physics is in a situation very similar to that of physics in the year 1900; all the clues were there to lead to quantum mechanics and Special and General Relativity, but the right physicists hadn't yet had the right brilliant insights into physics.

Along the way, he serves up lucid discussions of Einstein's theories of special and general relativity, as well as quantum mechanics.

Thankfully, Professor Greene understands that some of the subject matter is bound to be difficult to digest the first time through, and he alerts the reader to those sections that may require extra concentration. I especially enjoyed his descriptions of his collaboration with other members of the physics community, which convey the excitement of scientific discovery.

If you enjoyed "The Whole Shebang" by Timothy Ferris, you'll love this book. It left me with a new sense of awe regarding the universe at its smallest and grandest scales.

The remaining ten chapters discuss string theory, in which the contradictions between general relativity and quantum mechanics are settled by regarding the elementary particles not as points but rather as strings whose properties (e.g., mass, charge) are determined by how they vibrate. In the latter chapters, Greene also introduces us to M-theory, an extension of string theory which throws two- and higher-dimensional membranes into the picture along with strings and serves to unify the five different types of string theory that existed before 1995. As Greene eloquently shows us, there are a lot of very interesting things about the world according to string theory--perhaps the two that jump most immediately to mind are the properties of the six extra curled-up dimensions required for the theory and the types of tearing and sewing-back-together that (as co-discovered by Greene himself) the universe can undergo. Greene's own involvement in the development of string theory allows him to give us an interesting personal view of some of the theory's discoveries, and also made it easier for him to get candid interviews with the likes of Ed Witten, Cumrun Vafa, and many other heavyweights in the field. Especially near the end, this part of the book is somewhat heavier reading than were the first few chapters, but someone with a little bit of experience in undergraduate physics and/or a good deal of concentration and patience ought to be able to follow it pretty well, while most readers should still be able to get the basic ideas.

My main complaint about the book (and the main reason I'm only giving it 4 stars) is that it really doesn't come through quite as much as it should that string theory is still nothing more than a theory, with its development still very much in progress. Physicists don't seem to be anywhere near a point where they even really know what the basic equations of the theory are. It does make a fair number of predictions, but most of these won't be able to be tested experimentally in the foreseeable future. If and when physicists are able to write down and solve the equations of string theory (Greene doesn't attempt to speculate as to whether that's likely to happen any time soon), the results will be compared with what we already know, and if the results match up, it will be awfully hard to argue against string theory. But Greene seems to want to convey the discoveries of string theory as already being established truths about the universe, which seems to be pushing it a little bit.

However, whether or not its postulates are correct, string theory is extremely interesting--that's why I enjoyed reading this book, and I suspect that, when push comes to shove, that may be the biggest reason that string theorists devote their careers to studying it. 50 years from now, physicists may regard the science discussed in The Elegant Universe as an interesting historical diversion, or they may regard it as the foundations of a theory of everything--in any case, The Elegant Universe provides us with a lucid picture of the development of a fascinating branch of physics.

I picked up Brian Green's book with alacrity and wasn't disappointed. This book explains in sufficient but not too laborious detail the most recent advances in String/M Theory. Overall, the book is well structured and illuminating. Pitching with the right amount of detail and employing cogent analogies makes it a very easy read for a layperson. The one thing I would have liked, however, was a little bit of mathematical detail although I don't honestly know if this is feasible given the breadth of the topic.

Certainly a must read for anyone intersted in keeping abreast of the physics frontier, albeit it in an amateur way.

Its illuminating pages tells you where modern physics stands today and how it got there, and therefore where we as humans are in the understanding of who we are and how we got here.

My research on relativity and quantum mechanics has taken me through over 40 books that purport to explain physics; none quite has the the clarity and power of The Elegant Universe. If you are interested in this subject - start here. This book now sets the standard by which all other books must be judged, A kind of 'In Cold Blood', or 'Grapes of Wrath', of the scientific world.

Then in the end, book gets really interesting as author writes about Black Holes, reflects on cosmology and how strings, when incorporated, may change our understanding of a space-time.
Four ... stars for this.

I totally understand Brian Greene, why he is so enthusiastic and devoted to his research and why he writes with such a passion about it. Superstrings cosmology is a new promising and exciting field that may lead to better understanding of dark matter, vacuum energy and most importantly what the Big Bang really was. I tend to believe that all serious readers interested in cosmology should get accustomed with strings, because this theory is the only framework we have for understanding quantum gravity.

Greene goes on to discuss the development of string theory, from its infancy in the 1980s to the challenges it faces as research blazes ahead into the new millennium. Although I am skeptical of many parts of the theory, I above all respect its assertion that reality cannot be made up of dimensionless 'point-particles'--as Quantum Mechanics would have us believe.

Highly recommended: even for those only interested in learning about physics, regardless of string theory.

I should state my prejudice, as clearly as Brian Greene states his. I do not believe that we are smart enough to guess deep secrets without a scintilla of experimental evidence. String theory is not yet science, though it may become science. Whether it does or not, this easy-to-skim book will serve as an interesting sociological document.

It does an honest and courteous job setting up the problem that string theory addresses: the construction of a predictive quantum theory of spacetime. Personally, I found that the protracted metaphors tended to run away with themselves, and I soon tired of the girlfriend with her grenade, the problem of saving the world from a terrorist bomb, the child-hating landlord, Jim and Slim, and other less than elegant devices. Yet it seems from other reviews that these helped some readers, which is all that really matters.

The best part is chapter 9, which is frighteningly honest about the lack of evidence for either supersymmetry or strings. While there is no way of falsifying an idea, what are we left with? A choice of tailor. Brian Greene shops at Green-Schwarz-Witten the Tailors, catering for folk with a taste for divergence-free extended objects in the early universe. Being more conservative in taste, I shop at Dyson-Feynman-Schwinger the Tailors, who neatly remove infinities from the interactions of point particles, modelling processes on planet earth. About such issues of taste, there can be no useful discussion, beyond the obvious point that a diversity seems desirable.

The most lively part is chapter 11, where the author no longer speaks on behalf of a taste-group, but lets us know his personal excitement while helping to discover a really neat bit of math - mirror symmetry - which is right or wrong quite independently of physics.

The cloudiest part is chapter 12, for which a summary might be: M-theory will turn out to be the M-theory of M-theory.

This book should do no harm to science that has not already been done. In communicating the excitement of intellectual challenge, it may do good.

Best of all, string theory might turn out to be, like most innovations in science, a mixture of predictive new ideas and demonstrable mistakes. But I know only one reliable sieve for removing epicycles and dress sense: experimental testing of the best laid schemes of mice and theorists. It was a joy to work under that discipline in the 60s and 70s. Right now, we are less fortunate, in having a quantum theory of extended objects that has gotten to the age of 25 without ever receiving a birthday present from observation. Let us hope that its middle age is more exciting.