The present volume contains a selection of papers presented at the Fifth Conference on Collective Intentionality held at the University of Helsinki August 31 to September 2, 2006 and two additional contributions. The common aim of the papers is to explore the structure of shared intentional attitudes, and to explain how they underlie the social, cultural and institutional world. The contributions to this volume explore the phenomenology of sharedness, the concept of sharedness, and also various aspects of the structure of collective intentionality in general, and of the intricate relations between sharedness and normativity in particular. Concepts of Sharedness shows how rich and lively the philosophical research focused on the analysis of collective intentionality has become, and will provide further inspiration for future work in this rapidly evolving field.