Ron Jeffries posted this well known Kent Beck quote in the XP-mailinglist. They talk about the 2nd ed. of XP Explained by Kent Beck.

 But anyway, when I last asked Kent what XP is, he said
 "XP is a community of software development practices based on
 values of simplicity, communication, feedback, and courage".
 That was about two or three years ago.

 I look forward to seeing the second edition as well.
 I'm sure it will be enlightening ...