According to Fleck, a fact is not something objectively given but rather a social event. Scientific facts are no exception, as can be seen through the annals of medicine. Fleck argues that if the physical sciences initially appear to be immune to such social conditioning, this misconception can be corrected by recognizing the similarities between the natural sciences and medicine both historically and epistemologically. Fleck's ideas are not new, having been presented by him in 1935, but it was only recently that they have begun to strike a responsive chord. Kuhn was aware of Fleck's work when he began to promulgate his own ideas in the 1960s. But there are important differences as well as similarities which can only be appreciated once Fleck's own work has had a proper hearing. To this end the University of Chicago Press has published a translation-edition of the full monograph in 1979. In "On the question of the foundations of medical knowledge', Fleck's own précis to this major work, he correctly foretold the dawning of the sociology of cognition.