This paper examines how and why academics in different parts of the academy collaborate. In this paper we argue that: (1) There is a useful analytical distinction to be made between collaboration (fluid and expressive) and Collaboration (concrete and instrumental); (2) These two are not mutually exclusive and their use varies between disciplines; and (3) This distinction is an informative one for policy making that aims to encourage collaboration. Two interview based studies were used to explore the differences in collaborative practices across disciplines. The first was small and confined to a single university (n = 36) and the second was a larger study conducted in three countries (n = 274). Cross tabulations and analysis of open ended questions demonstrated many differences across the humanities, sciences and social sciences in collaboration. The C/collaboration distinction proves useful in understanding different disciplinary approaches to research, and in pointing to implications for research policy and funding. Attempts to increase collaborative research through Collaboration only, may well have deleterious effects on both collaboration and Collaboration. Research policy and funding should bear these differences in mind when seeking to stimulate collaborative research, so as to gain better outcomes across a range of disciplines.