The P4P Primer describes the evolution of the P4P pilot during the first three years of implementation. It provides the internal and external background and context for P4P, reviews P4P in detail (including discussions of its theoretical foundations, main components and underlying assumptions), and describes selected topics in the design of P4P (including establishing targets, partnerships and capacity-building activities, the roles of government and WFP, and gender strategies). Subsequent chapters examine risks, challenges and emerging lessons.