User Stories Applied: For Agile Software Development (The Addison-Wesley Signature Series) by Mike Cohn
The XP Values
Communication: Most desirable is face to face communication where we can talk, respond, gesture and draw on a whiteboard. Talking = good, documents = bad!
Simplicity: Focus on creating a solution to the problem faced today, not the problem anticipated tomorrow.
Feedback:Developers give and get feedback from pair programming, from automated tests, continuous integration. Customers are part of the team even sitting in the same space with the developers, and provide feedback through constant interaction with the team, and through acceptance tests.
Courage: They have courage to refactor their code, proceed with an overall master architecture.
The Principles of XP
Rapid Feedback: Constantly sending and receiving feedback, and responding to it.
Assuming Simplicity: Favor simplicity and attempt to create a simple solution before evolving to a complex one.
Incremental Change: Improve the software through small, incremental changes.
Embracing Change: Developers are able to adapt and accommodate change.
Doing Quality Work: Insist that the software consistently exhibits the highest level of quality workmanship.