Computer-Supported Co-operative Work (CSCW) is an interdisciplinary research area devoted to exploring the issues of designing computer-based systems that enhance the abilities of co-operating workers to co-ordinate and integrate their activities in an efficient, effective, and flexible manner. This selected volume represents both practical and theoretical approaches from many of the leading researchers in the field. As an interdisciplinary area of research, CSCW is characterized by bringing together widely disparate research traditions and perspectives into an arena of collaboration and contention. The selected papers reflect the diverse approaches and cultures of this multi-disciplinary field. This collection should be of interest to a wide audience because of the practical import of the issues and because of the interdisciplinary nature of the problems and the solutions proposed. In particular, the volume should interest researchers and professionals in computing, sociology, cognitive science and human factors.