I'm a big fan of eXtreme Programming. I've read XP Installed (the first XP book I read), XP Explained (the first XP book), and Planning XP. I must say I was a big disappointed in this book. Here's the problem: This book doesn't explain XP in enough detail to be useful as a first XP book. But at the same time it does try to explain XP concepts which are already known to anyone who's read one of the XP intro books (Installed or Explained), making it too basic for someone who's been using XP. That leaves this book some where in the middle, with a little bit of introductory material and a little bit of advanced material. I think it's a good second book on XP (read XP Installed first), but if you've been using XP (especially refactoring and test driven development) then this book isn't going to be very helpful for you.
Also the book is pretty thin and quite expensive for the small amount of content it contains. In my opinion you'd be better off buying Fowler's Refactoring book and downloading the JUnit docs, and reading Jeffries' XP Installed.