Fernando Vega-Redondo's self-contained account of the main contributions of modern game theory and its applications to economics starts with a detailed description of how to model strategic situations. The discussion proceeds by studying basic solution concepts and their main refinements; games played under incomplete information; and repeated games. For each of these theoretical developments, the text includes a companion set of applications that cover the most representative instances of game-theoretic analysis in economics (e.g., oligopolistic competition, public goods, coordination failures, bargaining, insurance markets, implementation theory, signaling and auctions).