XP or Extreme Programming developed in the late 1990’s begins with five values (Communication, Feedback, Simplicity, Courage and Respect) these are then further broken down into fourteen principles and further down into twenty four practices. The concept is that the practices are what a team does on a day to day basis while the approach and understanding is underpinned by the Values. Practices and Values need to be applied together to get the best outcome from this methodology and XP weaves the practices into a synergistic whole where each one is reinforced by the others and given purpose by the values. XP incorporates very strong testing emphasis based upon Test Driven Development (TDD).