This is one of the very few books I have ever returned to the bookstore (and I have bought thousands of books.)
Why don't I like this book?
1) It contains many, many, factual errors. These errors would be easily spotted by any freshman physics student, and should have been spotted by the publisher. For example, the author Robert Harley apparently doesn't understand the difference between electrical current and voltage.
2) It doesn't actually explain things. To me, an explanation shows how something works in terms of basic principles. Mr. Harley simpley states "facts", e.g., an outboard D/A converter will improve your sound, without explaining how or why.
3) Many photos and diagrams have mistaken or even irrelevant captions, leading me to conclude that Mr. Harley doesn't understand his own diagrams. For example, a diagram of an amplifier that uses feedback is used to "illustrate" a point about amplifiers that don't use feedback.
This last is the most serious point to me, because it makes me suspect that much of the technical-looking stuff in the book is included to impress the reader, not to actually explain things. In other words, it creates the impression of dishonesty.
To the people who defend the book as not intended for technical readers, I say this: even a non-technical book should be written by someone who understand the technical issues, so he or she can explain things clearly and truthfully. If it turns out that the author doesn't know the technical stuff, why should we read the book?
I might add that Robert Harley has a very poor reputation among respected audio engineers and other commentators in the field. Some audio manufacturers (but not all) pander to him apparently because he edits a high-end audio magazine, and his reviews can make or break a product.