The author has obviously spent quite a large amount of time around physics and programming, and it really shows throughout the book that he has taken the time to make sure that he not only fully explains himself, but also make sure he has explained an appropriate amount of depth for the engineer who simply wants to make usage of the concepts.
He does, however, make mention that he is primarily concerned with one particular kind of physics engine development (impulse based), and doesn't necessarily always makes full mention of alternative methods. He still does a decent job at explaining the core concepts along with increasing level of difficulty as the book progresses.
For somebody who wants the most basic form of physics, this book is not suitable for that purpose: it is an intermediate level book. The first chapters start out at a very basic level (note: it is obvious to me that the other review by the guy from China saying this book is only beginner level material didn't bother reading beyond the first two chapters), but the rest of the book is clearly not beginner level material.
However, this book is also not a substitute for a really advanced physics engine the likes of which Havoc and Ageia run off into. As well, the code implementations done by the author also reflect only an intermediate level of software engineering, but I admit that may just be an offshoot of simply trying to provide educational examples relative to the discussion.
Overall though, a very good read. Make sure it fits your requirements first though.