I examine the influence of James B. Conant on the writing of Kuhn’s Structure of Scientific Revolutions. By clarifying Conant’s influence on Kuhn, I also clarify the influence that others had on Kuhn’s thinking. And by identifying the various influences that Conant had on Kuhn’s view of science, I identify Kuhn’s most original contributions in Structure. On the one hand, I argue that much of the framework and many of the concepts that figure in Structure were part of Conant’s picture of science, a picture that figured prominently in the general education natural science courses that Conant taught at Harvard. On the other hand, I show that Kuhn’s Structurecontains important contributions that do not figure in Conant’s picture of science. I argue that the following three themes in Structure do not originate with Conant: (1) the concept of “normal science”; (2) “the problem of scientific revolutions,” that is, the apparent threat posed by radical changes of theory in science; and (3) Kuhn’s emphasis on the social dimensions of science, specifically the social structure of research communities.