The Theory of Games was conceived as a theory of interactive decisions for rational agents. The basic solution concept — that of Nash equilibrium — is built on rationality assumptions whose strength has only recently been made explicit. Refinements of Nash equilibrium, such as subgame perfection, require even stronger rationality assumptions. Here, it seems, is the pure domain of rational choice theory, where rational decision makers reflect on each others rational decisions, and rationality assumptions are multiplied by strategic interaction.