Studies in Science, Technology and Society supports projects that examine the social, intellectual, economic, and political contexts that influence the development and use of science and technology. This project focusses on diffusion of scientific knowledge and tests hypotheses concerning center - periphery relationships in information exchange. Four hypotheses will be examined in this project: how diffusion is increasingly globalized; how position in the global network of national scientific communities -- called the scientific world-system, is defined by the directionality of information exchange; how local centers exist more in certain disciplines than others; and how centrality is affected by research performance and collegial ties with foreigners. The international networks of knowledge diffusion will be measured by bibliographic citations given each year (1974-1986) by researchers in each major country to previous works from each major country (USA, UK, FRG, France, Canada, Japan, and USSR) in each discipline (clinical medicine, biomedicine, biology, chemistry, physics, earth and space science, engineering and technology, and mathematics). The project will yield knowledge about the strengths and limits of bibliographic citation analysis in developing an understanding of the structure and dynamics of creation and diffusion of knowledge among scientists and in nation-states. It will produce publications contributing to knowledge about the scientific world-system and reports serving domestic and foreign science policy. This study comes from well-qualified researchers. Research and dissemination plans are appropriate; institutional support is very good; the budget is modest. The project has important implications for our understanding of intellectual and social factors that influence development and diffusion of scientific knowledge. Support is recommended.