This book surpassed all my expectations, it was made for serious professionals, and that's what I wanted. Although I'm only an amateur photographer and Photoshop enthusiast, I'm enjoying the book, but because I'm very curious and exactly because I love Photoshop so much I wanted to understand everything about it.
If you are also an enthusiast/amateur but don't care about how this marvelous program works, you better get an easier book with canned "how toos". This book also has step by step guides, but on the top of it they explain every single detail of how everything works.
The authors give very in depth explanations on color theory, color management (I had a hard time on this), color spaces, exactly what is a digital image, etc. Although I found this all fascinating, as I already said I had a hard time trying to understand some concepts about color management, but my guess is that if you are a professional you will understand it better.
They also explain Bridge and Camera Raw. I understand why they included these 2 programs in the book (they work together, although CR is actually a plugin), but I could live without it, mostly because there are more in depth books about CR, like Real World Camera Raw with Adobe Photoshop CS3 (Real World), by Bruce Fraser and Jeff Schewe (I love this guy, check out his videos on CR at the Luminous Landscape website). If you don't plan on buying a specific book on CR, then the chapter about it is a good introduction.
The most fun part is of course on Photoshop itself, covered in a brilliant, flawless way, with everything you could wish for and more.
The book is massive, more than 700 pages, and is written in a nice, light but serious way. They won't waste your time and patience on endless silly jokes like Scott Kelby. For someone like me, whose mother language isn't English, I could understand everything and the reading flowed smoothly.