This book does its best, but in the end suffers from something that I think is inherent in the material itself. I did learn a little more about quantum theory from this book, but not much more than I already knew to begin with. And this book didn't really make many of the main concepts any clearer. I don't think is the author's fault, I think it's almost impossible to try to explain these things. Most of the problem, (and similar statements go for cosmology, cryptography, etc.) is that it's almost impossible to explain concepts whose fundamental expression is mathematical language without using mathematics. What inevitably results is some kind of vague, touchy-feely idea of what's meant, but little understanding. And I say this as a mathematician.
To give just one example, at one point in the book, the author talks about "probability amplitudes", for several pages. The only problem is, he never says what this term is supposed to mean, but he does mention that complex numbers are involved, and other facts. The result after this happens several times is that the reader starts to read entire paragraphs consisting of terminology that's never been defined clearly. The word "operator" is the best example here. It's fine to talk ABOUT operators in indirect, oblique language, but really you don't have a true understanding of what that word means unless you know its precise mathematical definition, or unless you have a clear understanding of the notion of vector space (axiomatically, not "stuff you can add together"). I didn't have this kind of problem with most of the mathematical terminology, because I know it, but the problem comes with the physics -- the physics concepts are essentially mathematical, and trying to explain them without using mathematics is like trying to understand Shakespeare without being able to read English -- you can always give a vague, hazy account, but not much more.
The book is well-written (aside from an overly-biased presentation of the philosophical aspects), but I think it tries to have its cake and eat it too. It says it's free of mathematics, but this isn't really the case. The whole text is fully of talk about operators, vectors, vector spaces, equations, probability theory, and so on. It's the _symbolism_, not the math, that's missing (except for the appendix, which thoroughly confused me, mainly because terms were introduced without precise definition, and the notation was the physicist's notation, not mathematician's notation...)
This book was confusing to me, but the reason was because it had too LITTLE math, not too much.