The article develops a transactional approach to studying science. Two concepts play a particularly important role: the institutional environment of science and scientific transaction. As an example, the North-American and Russian institutional environments of science are compared. It is shown that structures of scientific transactions (between peers, between the scholar and the academic administrator, between the professor and the student), transaction costs and the scope of academic freedom differ in these two cases. Transaction costs are non-zero in both cases, however. At the same time, it is hypothesized that a greater scope of academic freedom in the North American case may be a factor contributing to a higher scientific productivity.