I realized that after defending PP vigourously, it would be a good idea to second what Jon wrote about XP and the synergies of the practices. Which of course, Kent Beck stated already in the white book. (The XP’ers know what I’m talking about. To the rest, it’s the first of the commie XP books.). PP is a part of a bigger, grander scheme, and seeing is believing. (Now, this might be mistaken for some Scientology offspring. One of the main differences is that you are allowed to read the books. :-)