The widespread use of global networks like the Internet and mobile computing have made worldwide computing over virtual communities a reality. This is the first book devoted to community computing. It is based on the Kyoto Meeting on Social Interaction and Communityware, held in Kyoto, Japan, in June 1998. The 24 revised full papers presented together with an introduction to the emerging field were carefully selected and revised for inclusion in the book. The book is divided in parts on models and concepts, methodologies for large scale trials, sharing knowledge and preferences, supporting social interaction, and agent technologies in communities.