The chapter addresses three key aspects of the geography of scientific collaboration, namely: the growth of collaboration, the formation and evolution of its spatial patterns, and the impacts of research collaboration on science and regional development. It suggests the main theoretical concepts that can be used to explain the unprecedented intensification of spatially embedded research collaboration. The escalation of scholarly collaboration–in general and in its spatial dimension in particular–lies in the sophistication of contemporary science. The growth in scientific collaboration can also be theorised as a result of the changing role of science in contemporary society and the economy. The benefits from collaboration need to be examined in juxtaposition with the costs and risks of collaborative work–some of them directly associated with the geographical dimension of scientific collaboration. The probability of collaboration between people, organisations, or territories depends on the distance separating them: the lesser the distance, the higher the likelihood of collaboration.