This book isn't an introduction to quantum theory. Rather, it's an account of the various philosophical or metaphysical attempts to account for the strange behaviour of subatomic particles, in particular how they appear to need an observer to give them a definite position.

Considering the various interpretations of quantum theory, including the standard/Copenhagen and many worlds versions, the book explains the philosophical problems of each.

It uses a highly simplified model of quantum phenomena to give enough information to explain each interpretation, but it is in no way intended to be accurate physics. You are always conscious that you're working with an abstract generalisation rather than real science. So this is not a physics text, but more of a philosophical one.

Despite this, it throws in a fair amount of maths in the earlier chapters, with matrices, eigenvectors and complex numbers. If you can't understand his rather brief accounts - and even if you come from a mathematical, rather than a physics, background you'll find the notation's not what you're used to - don't worry. The later chapters don't depend on the maths except in a very small way.

Ultimately, none of the given accounts of the way quantum physics might work are wholly believable, but it is clearly a fascinating problem. Although Albert's style is flat and ungracious, and he tends not to uses analogies when they might be useful, it remains a good outline of the different approaches to the field.

If you're a lay reader and not scared of the maths, or if you want more theoretical background to your physics, this is a valuable book; however, don't expect to learn much of the quantum nitty-gritty.