The Road to Reality : A Complete Guide to the Laws of the Universe (Hardcover)

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Editorial Reviews

Amazon.com Review

If Albert Einstein were alive, he would have a copy of The Road to Reality on his bookshelf. So would Isaac Newton. This may be the most complete mathematical explanation of the universe yet published, and Roger Penrose richly deserves the accolades he will receive for it. That said, let us be perfectly clear: this is not an easy book to read. The number of people in the world who can understand everything in it could probably take a taxi together to Penrose's next lecture. Still, math-friendly readers looking for a substantial and possibly even thrillingly difficult intellectual experience should pick up a copy (carefully--it's over a thousand pages long and weighs nearly 4 pounds) and start at the beginning, where Penrose sets out his purpose: to describe "the search for the underlying principles that govern the behavior of our universe." Beginning with the deceptively simple geometry of Pythagoras and the Greeks, Penrose guides readers through the fundamentals--the incontrovertible bricks that hold up the fanciful mathematical structures of later chapters. From such theoretical delights as complex-number calculus, Riemann surfaces, and Clifford bundles, the tour takes us quickly on to the nature of spacetime. The bulk of the book is then devoted to quantum physics, cosmological theories (including Penrose's favored ideas about string theory and universal inflation), and what we know about how the universe is held together. For physicists, mathematicians, and advanced students, The Road to Reality is an essential field guide to the universe. For enthusiastic amateurs, the book is a project to tackle a bit at a time, one with unimaginable intellectual rewards. --Therese Littleton

From Publishers Weekly

At first, this hefty new tome from Oxford physicist Penrose (The Emperor's NewMind) looks suspiciously like a textbook, complete with hundreds of diagrams and pages full of mathematical notation. On a closer reading, however, one discovers that the book is something entirely different and far more remarkable. Unlike a textbook, the purpose of which is purely to impart information, this volume is written to explore the beautiful and elegant connection between mathematics and the physical world. Penrose spends the first third of his book walking us through a seminar in high-level mathematics, but only so he can present modern physics on its own terms, without resorting to analogies or simplifications (as he explains in his preface, "in modern physics, one cannot avoid facing up to the subtleties of much sophisticated mathematics"). Those who work their way through these initial chapters will find themselves rewarded with a deep and sophisticated tour of the past and present of modern physics. Penrose transcends the constraints of the popular science genre with a unique combination of respect for the complexity of the material and respect for the abilities of his readers. This book sometimes begs comparison with Stephen Hawking's A Brief History of Time, and while Penrose's vibrantly challenging volume deserves similar success, it will also likely lie unfinished on as many bookshelves as Hawking's. For those hardy readers willing to invest their time and mental energies, however, there are few books more deserving of the effort. 390 illus. (Feb. 24)
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Product Details

• Hardcover: 1136 pages
• Publisher: Knopf; 3rd Print edition (February 22, 2005)
• Language: English
• ISBN-10: 0679454438
• ISBN-13: 978-0679454434
• Product Dimensions: 9.4 x 6.5 x 2.2 inches
• Shipping Weight: 3.4 pounds
• Average Customer Review: 4.1 out of 5 stars  See all reviews (166 customer reviews)
• Amazon.com Sales Rank: #196,392 in Books (See Bestsellers in Books)

Customer Reviews

Most Helpful Customer Reviews

515 of 533 people found the following review helpful:

4.0 out of 5 stars Not for the faint of heart, November 16, 2004

By	MikeF - See all my reviews

The first half of this extremely challenging book takes the reader through huge swathes of mathematical territory - hyperbolic geometry, complex numbers, complex calculus, Riemann surfaces, n-manifolds and many more topics are covered.
These chapters don't just convey a general impression of each subject in laymans English, but make heavy use of formulae and mathematical notation, effectively letting the maths do the talking where a more 'pop' science book would be breaking out the strained analogies.
Although Penrose takes care to provide the reader with all groundwork necessary to understanding these subjects, this is still fundamentally difficult and unintuitive stuff and non-mathematicians will find that each page requires heavy concentration; skipping or skimming any part of these chapters renders later chapters unintelligible. Still, careful reading reaps huge rewards - the ideas these chapters cover are deep and beautiful.

The big payoff comes in the second half of the book, where the topics covered in the first half are applied to our current understanding of the nature of our universe.
Classical physics, relativity, various aspects of quantum mechanics, string theory and twistor theory (and more besides) are covered, and the first half of the book is revealed as a primer necessary to fully understanding this material.

It's worth repeating - this is a very, very heavyweight book for non-mathematicians. As someone with only a strong laymans knowledge of maths, I found most of the book very difficult indeed. I often had to read each chapter three or four times with a break in between each reading for the material to sink in. But reading this book was as good a mental workout as I've had in a long time, and the end result was that I feel like I've attained a much deeper understanding of the nature of realiy than any book written in plain English could ever convey. The only reason I'm not giving the book 5 stars is that the difficulty of the subject matter makes it fairly inaccessible, albeit necessarily so in my opinion.

If you do get this book, good luck, and don't give up!

201 of 206 people found the following review helpful:

3.0 out of 5 stars Roadmap Not Road, December 18, 2005

By	C. Jackson (Bucks, England) - See all my reviews (REAL NAME)

Let me confess at the outset that I have a PhD in theoretical physics that I gained in 1969. The subject matter was quantum electrodynamics. However, I have worked my entire life in the computer industry. Despite this, I have always kept a background interest in physics. I've retained quite a lot of my original mathematical knowledge but have obviously become relatively rusty. Over the years, I've enjoyed reading several of Roger Penrose's books and found all of them provocative. I bought this book because I thought it would quickly explain to me the latest ideas involved in reconciling relativity and quantum mechanics and lead me to the most recent ideas in dealing with gravity waves, for example.


The book started with a disarming claim to be able to teach a non- mathematician sufficient of the maths to be able to follow the arguments being set out. It even invited the reader to skip the detail of the maths where this became an obstacle. With my background, I therefore settled down for an engaging read. Boy, was I in for a surprise!

The alarm bells began to ring when early on, I passed through the explanations of calculus. Although I obviously had no difficulty in understanding Penrose, I could easily see that a neophyte would not be able to pick up the subject with the limited explanations given. Soon, at around 300 pages in, I crashed into a personal lack of knowledge and, sure enough, Roger Penrose's explanations left me floundering. As a result, I had to put the book to one side and fill in the gaps in my knowledge from other sources. Eventually, I was able to return to the book. However, this became a recurring process - I found that, on several occasions, I had to put the book to one side and educate/re-educate myself from the texts of others.

This meant that this book was a real struggle to read. It became clear at many points that the mathematical jargon was so intense, that during the editing process, the author had lost sight of the exact state of knowledge that the reader would have achieved. This meant that the intense bouts of correct mathematical terminology and descriptions frequently formed impenetrable barriers to explanations.

The whole book gave the impression of being an honest attempt to lead the reader up a very long slope indeed (more than a PhD's worth) and into a sufficient state of education that he or she would be able to read and understand the concepts and detail of Twistor Theory, Roger Penrose's speciality in this subject matter. For me this failed. I found the chapter on the latter to be the most incomprehensible part of the book, which I thought was a pity after all the effort that I had put in as a reader and that Penrose had put in as an author. In all fairness, Penrose does make it clear that his Twistor Theory is not in any way mainstream.

What does come out very clearly indeed is that Penrose believes that a whole new breakthrough is needed to reconcile quantum mechanics and relativity - and that what is around today is not up to it, despite the enthusiasts behind the most popular approaches: string theory and loop quantum gravity.

As I read the book, I kept hearing the voice of my old postgraduate supervisor saying, "Where's the physics? You can't just keep churning the mathematical sausage machine. Where's the physics? That's what really matters!" Unfortunately, I felt that this book suffered from just that. And that gave me the impression that today's theoretical physics had left physics behind. If that is true, then this book, for all its problems, has succeeded in making this clear. If it is false, then this book has done physics a disservice.

Roger Penrose is obviously a brilliant mathematician. Equally obviously, he has no real concept of just how little mathematics ordinary mortals know or can even absorb. At the end of my reading of the book, it was abundantly clear how very much I did not know. On the positive side, it did provide a good roadmap of the gaps in my knowledge that I had to be prepared to fill in if I really wanted to be able to understand the subject! This, I felt, was the book's real strength. Perhaps it should have been better titled "The Roadmap To Reality".

This book is not for the casual reader expecting a breeze-through read like Hawkings' "A Brief History of Time".

495 of 526 people found the following review helpful:

5.0 out of 5 stars A panorama of science., February 26, 2005

By	Palle E T Jorgensen "Palle Jorgensen" (Iowa City, Iowa United States) - See all my reviews (REAL NAME)

It's a delicate balance for book: Encyclopedic vs well focused on a unifying theme!

Penrose succeeds admirably. It's not boring! Books like this are few and far between. Indeed, there are preciously few authors who manage to successfully guide beginning students into serious scientific topics; and even fewer who can see the big picture, and do it all. And then keeping our attention through more than 1000 pages! Penrose's book is inspiring, informative, exciting; and at the same time it's honest about what math and physics are. It is modest when modesty is called for. You are not cheated. You do get the equations (not just hand waving!), but you are gently prepared in advance, so you will want the mathematical formulae. Penrose's book is likely to help high school students getting started in science; and to inspire and inform us all. There is something for everyone: for the beginning student in math or in physics, for the educated layman/woman (perhaps the students' parents), for graduate students, for teachers, for scientists, for researchers; and the list goes on.
It is one of the very few books of this scope that is not intimidating. Not in the least!
I can't begin to do justice to this terrific book. Get it, and judge for yourself. I will also not give away the ending, other than saying that the title of the book is a good hint. And you will be able to form your own take, and your own ideas on the conclusion. Like with all good and subtle endings, they can be understood and appreciated at several levels.

I came across Penrose's book in my bookstore by accident, and I was at first apprehensive: The more than 1000 pages, and the 3.3 pounds are enough to intimidate anyone. But when I started to read, I found myself unable to put it down. And I didn't: Bought it; and I had several days of enjoyable reading. I am not likely to put it away to collect dust either. It is the kind of book you will want to keep using, and to return to.

It will not surprise that one of Penrose's unifying themes is the compelling and pleasing geometric images that underlie both the mathematics (roughly one third of the book: modern geometry, Riemann surfaces, complex functions, Fourier analysis, visions of infinity), and the physics: Cosmology (the big bang, black holes), gravity, thermodynamics, relativity (classical and modern: loop quantum gravity, twisters), and quantum theory (wave-particle duality, atomic spectra, coherence, measurements).

The pictures: In fact, this semester, I was just teaching a graduate course, and I had a hard time presenting of Riemann surfaces in an attractive way. It's a subject that typically comes across as intimidating in many of the classical books: Take Herman Weyl's book, for example. I also found it refreshing to see that Roger Penrose gave the many illustrations his own personal and artistic touch; as opposed to having flashy pictures generated by the latest in color-graphics and special effects. I think readers will relate better to Penrose's own illustrations: They isolate and highlight the core ideas and they are not intimidating: We sense that we ourselves would have been able to make similar pencil sketches. Or at least we are encouraged to try!

The common theme in the pictures serves to bring to life the underlying and fundamental ideas;--- another attractive feature of the book! It is otherwise easy to get lost in some of the equations, and in the encyclopedic panorama of topics. Review by Palle Jorgensen, February 2005.