One of this book's co-authors, Brian Cox, is the most famous living physicist in Britain these days, thanks primarily to his two impressive BBC series on the solar system and the universe.
The success of those series was down to Cox's soft- spoken yet passionate enthusiasm for his subject matter, which helped the viewer take in the mind-boggling scale and big ideas contained therein.
It has to be said that most non-scientists coming to this book on the back of those television shows are probably in for a nasty shock. Cox and Forshaw, both highly eminent and qualified in their fields, have co-written a book before, Why Does E=mc2?, which tackled Einstein's theories of relativity. This time, as the title suggests, they're delving into the somewhat weirder world of quantum mechanics: essentially, how the universe behaves at the sub-atomic particle level.
And it's a struggle. This reviewer has a first in physics and a PhD in experimental nuclear physics and, while I managed to follow it all, there were times when it felt as if I was wading through a thought-swamp. Although not overtly mathematical – except for a rather tangential and unnecessary epilogue about white dwarf stars – there is still quite a lot of detailed theoretical stuff that I suspect will leave many readers nonplussed.
The book starts really very well. With brightness and gusto, the opening chapters deal with the culture shock that thinking about the subatomic world entails. The trouble with quantum physics is that it involves completely disregarding the common sense that we glean from our everyday experience of the macroscopic world. Cox and Forshaw's way into all this is standard: to look at the wave-particle duality of light. In some circumstances, light behaves like a stream of particles; in other circumstances it behaves like a wave. So which interpretation is correct? The quantum answer is: both and neither. If you can't get your head around that, this probably isn't the book for you.
A stream of experimental data has flooded in over the past century, and swept away the old assumptions of classical physics. As Cox and Forshaw put it: "A key feature of quantum theory [is that] it deals with probabilities rather than certainties, not because we lack absolute knowledge, but because some aspects of Nature are, at their very heart, governed by the laws of chance."
So we discover that particles can be in two places at once, everything that can happen does happen, and movement is an illusion. Cox and Forshaw initially deal with these seeming paradoxes well, and to begin with hold the reader's hand through it all. But things take on an altogether more serious feel soon enough, and we're swimming in a sea of wavefunctions, potential wells and eventually anti-matter.
Occasionally, the authors lift their heads from the whiteboard and take a look around at the real world, which comes as some relief. When they do, they are good at drawing connections between seemingly esoteric theory and everyday practicalities. The discussion of the development of transistors from quantum theory, for example, is clear and concise. But such lucid passages only serve to show up the stodginess of the more theoretical sections, which are probably better dealt with in standard textbooks. Enthusiasm and passion for your subject matter is great, but sometimes it can only take you so far.