The story is the unit of functionality in an XP project. We demostrate progress by delivering tested, integrated code that implements a story. A story should be understandable to customers and developers, testable, valuable to the customer, and small enough so that the programmers can build half a dozen in an iteration.

– Kent Beck, Martin Fowler, Planning Extreme Programming

It’s time for me to brush up on the role of the customer in an XP project. I’m going to be taking part in an XP tutorial at OSCON next Tuesday which is the only reason I’m reading XP books whilst on holiday.