Extreme Programming is a discipline of software development 
based on values of simplicity, communication, feedback, and 
courage. It works by bringing the whole team together in 
the presence of simple practices, with enough feedback to 
enable the team to see where they are and to tune the 
practices to their unique situation.

In Extreme Programming, every contributor to the project is 
an integral part of the "Whole Team". The team forms around 
a business representative called "the Customer", who sits 
with the team and works with them daily.