Customer Reviews
very difficult masterwork - By: bbdude, 17 Sep 2008 
Many of the reviews focus on the fact that this book is difficult to read. It is. The information content is dense. Arguably not as dense as a technical math or physics book, this is a technical work, & requires a very slow process of reading & re-reading.
My opinion is that those with an understanding of calculus will get the most out of this book. If you reallly do not understand partial derivatives & integrals, I think you're in for a tough road.
There was math in this book that was unfamiliar to me, specificallly Lie algebras, Lie derivatives, calculus on manifolds, & fiber bundles. These chapters were very slow going.
However, if you assiduously go through every sentence until you understand its meaning, if you consult outside references as necessary, if you reallly absorb this material- it is phenomenal. Penrose will equip you with a visual & intuitive comprehension of the advanced math necessary to reallly understand the big theories of physics. You won't be able to do calculations & solve problems, but the intuitive understanding is primary- & if you decide to go farther & look into reallly solving physics problems, you will be ready to learn quickly & easily.
In terms of the breadth & scope, I could compare this to the Feynman lectures. Feynman was far less stiff in his explanations- but if you reallly follow Penrose, his presentation is both elegant & thorough.
The book splits into 3 sections. The math background is followed by a very fine summary of the two big theories of modern physics- relativity & quantum mechanics. Finallly, at about page 700, Penrose starts to discuss speculative ideas on the frontiers of physics. He carefully denotes where his own ideas differ from those of other theorists. By this time, having laid a full groundwork, Penrose addresses the reader as almost a technical peer. This is not dumbed down.
This is a book to live in for a long time. There is nothing else quite like it. The rewards justify the large amount of reader time & effort that will need to be committed. Five stars, absolutely.
Fantastic Book, though not for the true layman - By: Ted Maxwell, 27 May 2008 This book is a real tour-de-force. My A-Level Maths of 18 Months ago was definetley a sufficient starting block for understanding almost everything in the book to an o.k. sort of standard, i plan to read it through at least twice more to make sure i reallly understand everything to the level that i want to. (I'm doing a MSc in Mathematics now, but plan to Do a 2nd MSc in Theoretical Physics later on, as that is where my true interests & ambitions lie) The explanations of the physics are possibly even better than those of the mathematics, although it is virtuallly impossible to reallly understand quantum mechanics without many years of proper study, this book reallly gives a nice intro to the wierd & wonderful world of the quantum.
Not a book for the "popular science" market - By: Mr. A. D. Rowley, 21 Feb 2008 
I'm an extremely keen reader & viewer of what is now commonly callled Popular Science. I have a great amateur interest & knowledge of cosmology, quantum physics & related physics. I am also a (qualified) & pretty darn good computer programmer in languages from BASIC to 68000 assembly language & have contributed to professional games releases & written 3D engines, amongst other things.
I haven't said this to show-off how smart I am by any means, merely to illustrate just what an Everest this book is to the casual reader, including myself.
If one were to pick this book up from the shelf & note the blurb on the back which says "It assumes no particular specialist knowledge on the part of the reader" & that "the early chapters give us the vital mathematical background", you might assume that it was accessible to pretty much everyone who had the capacity to read, learn & could add up.
Not so. This blurb is seriously misleading, requiring at least- in my view- an understanding of mathematics to college level, if not university level.
It is true that the early parts of the book are largely devoted to explaining the maths involved to getting deeper into the physics of the rest of the book, but from very simple beginnings they rapidly falll into a whole host of symbols & equations most people won't understand. Including myself.
We start off with mathematical proofs, which are nicely explained, interesting & fairly straight forward for the novice to get to grips with, but are then remarkably quickly plunged into the topic of hyperbolic geometry & the terrible, mystical symbols crop up without any explanation of what they mean.
It's been said that once can fill in one's gaps of knowledge on the maths involved here by Googling the terms & studying the results, & that the book then opens up quite well to the reader- I've even seen it suggested that one can do it a page-a-day. That may be true, but I find Googling symbols rather difficult & I also think that studying a page-a-day of a 1000+ page book might require a lot more commitment than the interested amateur would be prepared to give.
From what I can ascertain, this book is- in its scope & ambition- a bit of a stunner & pretty much a definitive guide to most of the current thinking in the world of physics. For that reason, I'd dearly love to be able to read it.
However, the assertions of "no specialist knowledge" is extremely misleading. I can't help feel that, if the author had spent a dozen or so more chapters at the beginning explaining the maths & symbols behind the maths & symbols in the next dozen or so chapters, the reader would not only be much more involved but much more educated & willing to tackle the rest of the book.
As it is, I've put the book aside rather quickly until I can educate myself in the mathematics involved to even begin to get beyond the first few chapters.
A bit of a missed opportunity, in my view & this is solely why I have given it such a low star-rating- I have no doubt the book is excellent on its topic; probably worthy of a five-star; but to mislead the buyer by its blurb is rather unforgiveable. Probably the fault of the publisher rather than the author, admittedly, but the author could have offered more by way of a foundation class in the maths needed.
For the mathematically literate only - By: Matt Westwood, 30 Dec 2007 
Sorry but you *have* to understand your maths before you can get to grips with this. As for me, I've got an MMath with Quantum Mechanics & Electromagnetic Theory under my belt, but I was *still* having trouble with it.
If anyone can explain the mathematics behind the state of play of theoretical physics, then surely Penrose can. His style is not quite as impenetrable as it was for some of his earlier works, but it's not as easy as you'd like it to be. Having said that, I wouldn't be able to do any better so fair play to him.
I struggled through to the end (and I admire anyone who managed six chapters & commiserate with those who couldn't get that far) but I still feel short-changed by my own mathematical limitations as I had to take so much of it on trust (and sorry, but life was too short to do the exercises, I've got too many other projects on the boil).
I have a dream of being able to boil this thwacking great tome down into an account that "the layman" *will* be able to appreciate, but by the time I'd have managed to do that, it would be out of date. Apparently things move faster than you'd think out on the edges of thought.
If you can't quite handle the mathematics in this, but want to, then it's worth considering whether to take a degree in the subject. If this book encourages anyone out there to embark on such a course of study, then it's more than paid for itself.
Very hard going - By: DP, 06 Dec 2007 This book is supposedly for the intelligent layman. However, Penrose's cutoff point is clearly quite high, & I for one failed to make the grade. Penrose starts slowly but suddenly after a couple of chapters it gets very technical. The actuallly quality of the softback copy I read was terrible & started to falll apart. This meant going back to re-read sections became difficult. I also suspected that there were some typos in my edition. I found it so hard going that I gave up before I had reached halfway. It gets 2 stars rather than 1 simply because it did stimulate me to think.
