Many of the things we do, we do together with other people. Think of carpooling and playing tennis. In the past two or three decades it has become increasingly popular to analyze such collective actions in terms of collective intentions. This volume brings together ten new philosophical essays that address issues such as how individuals succeed in maintaining coordination throughout the performance of a collective action, whether groups can actually believe propositions or whether they merely accept them, and what kind of evidence, if any, disciplines such as cognitive science and semantics...