This study examines one particular kind of network - the "knowledge network" - whose primary mandate is to create and disseminate knowledge based on multidisciplinary research that is informed by problem-solving as well as theoretical agendas. In their examination of five knowledge networks based in Canadian universities, and in most cases working closely with researchers in developing countries, the authors demonstrate the ability of networks to cross disciplinary boundaries, to blend the operational with the theoretical, and to respond to broad social processes. Operating through networks, rather than through formal, hierarchical structures, diverse communities of researchers create different kinds of knowledge and disseminate their results across disciplinary, sectoral, and spatial boundaries. Analysis of networks in health, environment, urban, and educational fields suggests that old categories of "north" and "south" are becoming blurred, and that the new structures of knowledge creation and dissemination help to sustain collaborative research.