There are many walks of life in which teamwork is found and in which, by common consent, it could be better. Yet even the most basic questions about teams remain unresolved. What makes a group of individuals a team? Does teamwork involve a special type of reasoning? What makes teams successful? How do we learn to be team players? This volume brings together, for the first time, contemporary research from across the social sciences, addressing such questions from a variety of theoretical and empirical perspectives.