Rod Hilton's Absolutely No Machete Juggling blog has a review of The Art of Agile Development. Here's an excerpt:

That said, this is an excellent book on XP. All of XP's practices are covered in just the right amount of detail - giving you enough information that you can adopt the practice, but requiring that you do additional research about the ones that interest or challenge you the most. This allows the book to be a pretty quick read in general, which is beneficial for a team wishing to adopt XP practices soon. This level of detail does have one disadvantage, though: by staying largely in the realm of hypotheticals and ideals, I often found myself thinking that the authors were being naive and idealistic about how easy some practices were to adopt. This made me somewhat more skeptical of the book than I would have been if more detail had been offered, but ultimately I felt the level of detail was right; I did my own research online about some of the things that challenged me.

Read the full review here.