This book contributes new insights into the organization of free/open source (F/OS) software communities by examining the links between learning, division of labour and commercialization, demonstrating the need for a synthesis of work on both community organization and cooperation to understand F/OS community dynamics. These aspects are examined in the light of detailed case studies of the GNOME and KDE projects. This book offers an innovative theoretical framework, a critical assessment of various methodologies for examining the organisation of F/OS communities, and a typology of commercial involvement in F/OS.  The analysis reveals the diversity and evolution of F/OS communities and their connections with other socio-economic networks and institutional practices. The insights afforded by the book have implications for future research and the design and implementation of open source efforts.