This report attempts to understand the growing trend of international scientific collaboration as a preferred method of building scientific capacity in developing countries. Before the effects of these trends can be documented, however, there is a need to better define scientific capacity itself. This is relevant not only as an end in itself but also as a means of identifying potential collaborators. The traditional dichotomy of developed and developing countries no longer seems to serve the purpose of increasing useful understanding of these trends. The report attempts to provide a new index of scientific capacity based on an aggregation of several national-level measures and creates a useful taxonomy of countries categorised by scientific capacity. The four classifications arising from this taxonomy are scientifically advanced, proficient, developing, and lagging countries. It examines the trends in output, productivity, collaboration and linkages between and among countries in each of these categories.