[This page was triggered by my speculative statement that XP may not be a method in the traditional sense. The answers below more successfully express what I was trying to say. --FalkBruegmann]
As taught by KentBeck, XP is a method. He certainly tells you what to do and what not to do. It is quite different from the typical methodology, but it has just as much detail as they do. It is just as vague, too, but it is vague about different details. For example, they tell you how to document your system but don't talk that much about how to tie your tests to your code, while XP focuses on tests and doesn't say much about documentation. --RalphJohnson
I agree that XP is a method, but it also appears to be a worldview. Cf. WuWei. I've actually taken a stab at integrating XP, MSF and RUP with a tentative blessing by the XP folk, and will be making an outline of this available online in the next week. --PeterMerel
Is XP MethodOrMethodology? XP is a methodology that contains a method for developing a fragment of software. The methodology is the whole thing, the method is the piece of it advising YAGNI and RefactorMercilessly and UnitTest. --AlistairCockburn
see also IsXpaProcess
WhatHappened since last change in 2001? Any further thoughts? Please also checkout question about XP alternatives in IsXpIndependentOfObjects? --DavidLiu