Game theory provides a mathematical tool for multi-person decision making. The aim of this module is to provide an introduction to game theory, studying basic concepts, models and solutions of games and their applications. Major topics: Games of normal form and extensive form; Applications in Economics; Relations between game theory and decision making. Games of complete information: Static games with finite or infinite strategy spaces, Nash equilibrium of pure and mixed strategy; Dynamic games, backward induction solutions, information sets, subgame-perfect equilibrium, finitely and infinitely repeated games. Games of incomplete information: Bayesian equilibrium; First price sealed auction, second price sealed auction, and other auctions; Dynamic Bayesian games; Perfect Bayesian equilibrium; Signaling games. Cooperative games: Bargaining theory; Cores of n-person cooperative games; The Shapley value and its applications in voting, cost sharing, etc.