The question addressed in this challenging new book is: What binds societies together and prevents them from disintegrating into chaos and war? Elster analyzes two concepts of social order: stable, predictable patterns of behavior, and cooperative behavior. The book examines various aspects of collective action and bargaining from the perspective of rational choice theory and the theory of social norms. It is a fundamental assumption of the book that social norms provide an important kind of motivation for action that is irreducible to rationality.