Economists have in recent years found the theory of games to be an attractive route for exploring imperfectly competitive markets. In this collection of articles, some of the best minds in contemporary economics on both sides of the Atlantic xplore both the potential and the limitations of this theoretical framework. In a lengthy introduction, the editors conduct a comprehensive survey of the hypothesis of game theory and its goals which provides a unique perspective on the subject. At the same time, they warn the theory is not sufficiently well developed to provide an analysis of all games. The papers which follow fall into three sections: equilibrium theory, imperfect competition and the design of organizations. Together they explore and illustrate many aspects of the economic application of game theory in industrial organization.