The Commons, as an idea and practice, has emerged as a new social, political and economic dynamic. Along with the market and the state, the Commons is a third mode of societal organization. The Commons and Peer to Peer (P2P) together form a system based on the practices and needs of civil society and the environment it inhabits, evolving away from obsolete, centrally planned systems or the competitive dictates of market economies. But what are the Commons and P2P, and how do they interrelate? This Primer explores these concepts.