 This outline has focused on some basic background regarding the Prisoner’s Dilemma and emergence of cooperation. More recently a generation of richer game-theoretic models has appeared, using a wider variety of games of conflict and coordination and more closely tied to historical precedents in social and political philosophy. Newer game-theoretic analyses of state of nature scenarios in Hobbes appear in Vanderschraaf (2006) and Chung (2015), extended with simulation to include Locke and Nozick in Bruner (forthcoming).