"The programmer is the heart of XP" - Kent Beck
eXtreme Programming
Extreme Programming, or XP, is a lightweight discipline of software development based on principles of simplicity, communication, feedback, and courage. XP is designed for use with small teams who need to develop software quickly in an environment of rapidly-changing requirements. - URULINUX
The downside: for a critical view of XP, check XP Refactored - The Case Against XP by Stephens and Rosenberg. The book is somewhat repetitive and could use more substance, yet containts some interesting ideas. Reviews can be found here, here and of course at the Amazon web site. ? MatiasH
eXtreme GX
Extreme Programming from a CMM Perspective