The first chapters of the book explain a little bit about Agile and its methodologies, practices, and background. The subsequences are all about reviews of refactoring, design patterns, testing, and related stuff. Also, there are some study cases at the end of each topic.
Even though this book is not a breakthrough--there isn't something new--but the depth of the reviews makes the book worth reading. You'll recall many topics like Refactoring, XP, TTD, etc etc. You'll learn it more deeply because the author gives different perspectives on how to use certain techniques.
What bothers me a lot about this book is the author's word selection. Bob is a Sesquipedalian: he likes using big words. Some selections cause the book to be unreadable.
Also, some explanations are just too shallow. Sometimes, the author likes to assume that the readers have an understanding of the prerequisites, so he didn't give so much time explaining it or explaining it in a vague way. This is frustrating. I had to skip two case studies because of their lack of explanations. I'd tried it hard, seriously, but I don't think I would ever understand with that level of unclarity.