The Road to Reality: A Complete Guide to the Laws of the Universe [Hardcover]

Eventually History remembers the great books - "The Road to Reality" is a true work of art, destined to be a classic - It is the first genuine attempt to cover in one book the state of theoretical physics today. Where other popular science books attempt to simplify the theory and omit equations, thereby reducing themselves to talking about the theory ... "The Road to Reality" PRESENTS the theory. It is a subtle, but important difference that I will try to illuminate in the rest of this review.

"The Road to Reality" makes the modern theories of physics easily accessible to mathematicians and layman alike, in a self-contained text. It achieves this by virtue of being the first popular science book on theoretical physics to devote its first 16 chapters to introducing the reader to the pre-requisite Mathematics and `Philosophy of Science' necessary to understand the theoretical physics presented in chapters 17 to 34. The book is littered with necessary equations, but all are introduced in a logical, intuitive manner and provided with some of the best explanations in words and pictures that I have seen to date.

As such the equations can be viewed merely as markers in the text if reading as a popular science book. Conversely they can be used to guide the serious theoretical physicist in attempting the minimal but carefully chosen and difficult exercises, and any mathematical investigations the reader may be inspired to conduct themselves upon reading the beautiful exposition of physical theories of our universe.

As justified above, the best thing about the book is its 1094 pages can be read at various levels .... from a cursory glance (genuinely constituting popular science, albeit a difficult read) or as serious academic study (taking you well into a post-graduate level appreciation of mathematics and theoretical physics). For the academic, it will accelerate your path to becoming a rounded theoretical physicist. Every school should own this book and every potential student of maths or theoretical physics should attempt to read it pre-university.

There is no room for dubious analogies in "The Road to Reality", which removes the scope for confusion. Apologies to those readers who like analogy, but there is no place for it in theoretical physics - Communicating an understanding of what the theory is really about, to a level that it seems intuitive to the reader, is the goal of this book.

It's my favorite book of all time. I can't recommend it more highly than that!!

When choosing the rating for this book I doubted between 5 and 1 stars. Why?

Well even for someone with some mathematical background (although it's been quite some time ago) this book is tough. If you're not mathematically minded you're better of with a book with less formula's and numerical examples. Although Penrose states many times one can just read "over" the more difficult parts and still get the gist of the story, I tend to disagree. His is a beautiful treaty on the most important mathematical theories that we have at the moment and that are used in physics or more specifically cosmology. He builds a well thought out "story" that should give the reader a thorough insight in the building blocks of physical theories. If you skip over the mathematical explanations you miss the basis upon which the rest of the book is leaning. I think some understanding (more then just basic) is necessary to appreciate the wonders of cosmology, at least as presented in this book.

If on the other hand you have a firm grip on maths and are not afraid to extend this knowledge, then Penrose will keep you busy for many weeks and lets you peek at the wonders of cosmology.

So depending on your scientific background and appetite for maths, this is a great adventure or frustrating Herculean task.

This is an exhaustive review of the laws of physics as related to physical reality with significant emphasis on the mathematical component. The author is an outstanding mathematical physicist of our times, and in this book of 1100 pages, he describes the concept of space, time, and matter (energy) in terms of classical physics, quantum physics, string theory and its derivatives.

In physics, the behavior of objects is understood in terms of the action of a force; a vector quantity, which has both magnitude and direction. The force acts on a matter and produces a causative action that results in an effect. The cause - effect is one of the fundamental aspects of classical reality, but it gets fuzzy and uncertain at submicroscopic levels (quantum physical reality.) The main object of physical law is to describe the reality we observe. Our observation includes this universe that is made of space, time, matter, and energy. All objects are made of matter, which exists as complex structures composed of molecules, atoms and fundamental particles. Matter is also a form of energy and the two forms can interconvert as described by the Einstein's famous equation. The fundamental particles has certain physical properties and the manner in which energy (and force) is expressed is though their association with the so called force particles that are responsible for four fundamental forces that operate in nature, they are; electromagnetism, gravity, strong and weak nuclear forces. The four forces mediate matter-matter interaction and facilitate matter-energy conversions in spacetime and thus explain physical reality. The key to the understanding of nature and physical reality is to discover a theory that satisfactorily explains all the four forces and this theory must be experimentally verifiable. Unfortunately, this has not been achieved so far, but we have theories that can be verified but explains only three forces. One single physical theory that explains both quantum and classical realities have not been successful mainly because the nature of gravitational force (curved spacetime) is difficult to describe in a unified situation, since space and time at the most fundamental level are also quantized (exist in discrete quanta) and are they dynamic (not static background).

To understand this book the reader is required to have undergraduate level physics and mathematics; the author explains in the introductory part of the book why he chose to include mathematics despite its negative impact on the book's marketing potential. It would suffice to say that the interplay between mathematical ideas and physical behavior played an important aesthetic role in the minds of great physicists, and Albert Einstein is one of the most important figures in being attracted aesthetically to a particular idea. You can skip chapters 1-16, and from chapters 17-30, general discussion about geometry of spacetime, quantum physics, quantum field theory, quantum cosmology and the standard model of particle physics is presented. I found the last four chapters to be most interesting.

A brief summary is as follows: The unification of special relativity and quantum theory led to quantum field theory (QFT) which produced a minefield of infinities, but with some ingenuity, the infinity problem was circumvented leading to standard model of particle physics which is in good agreement with nature. The controversy between the quantum relativity group and the QFT side is that the latter group tries renormalizability or finiteness as the primary goal, but the former group likes to solve the conceptual difficulties between the two theories. The combination of two theories of particles physics into one framework to describe all interactions of subatomic particles, except due to gravity, is called standard model. These two theories are electroweak theory and quantum chromodynamics. They describe force interactions between particles in terms of exchange of intermediary particles. The author also engages the reader in an insightful discussion of many other theories.

1. The Emperor's New Mind: Concerning Computers, Minds, and the Laws of Physics (Popular Science)
2. What is Life?: With Mind and Matter and Autobiographical Sketches (Canto)
3. Quantum Physics: Illusion or Reality? (Canto)