The concept of social capital, or the value that can be derived from social ties created by goodwill, mutual support, shared language, common beliefs, and a sense of mutual obligation, has been applied to a number of fields, from sociology to management. It is only lately, however, that researchers in information technology and knowledge management have begun to explore the idea of social capital in relation to their fields. This collection of thirteen essays by computer scientists, sociologists, communication specialists, economists, and others presents a multidisciplinary look at this particular intersection of information technology and social science and the need to adopt a sociotechnical perspective. For the most part the contributors take a positive view of the interplay of social capital, knowledge sharing, and community building. Some essays look at specific instances, including the on-line and face-to- face relationships of a community of athletes, the building of social capital among Iranian NGOs, and the Internet-based communities created by the open-source movement, while others discuss more general ideas of civic and personal communities. The last four essays examine computer applications that augment social capital, including topic- and member- centered communications spaces such as the Expert Finder and the Loops system and virtual repositories of knowledge such as the Answer Garden and Pearls of Wisdom.