One difficulty in studying “astronomers” and “mathematicians” as distinct classes in ancient China is that the important ones were neither specialists nor professionals, but polymaths, with little to distinguish them from any other intellectual. Another difficulty, confounding any modern taxonomy, is the tight relationship between astronomy, mathematics, Classical exegesis, and ritual. This article uses the thousands of lost and extant works cataloged under discrete emic categories in the Hanshu, Suishu, and Jiu Tangshu bibliographic treatises to weigh the place of the sciences and their practitioners vis-à-vis other contemporary forms of knowledge and, using polymathy as a vector, to map the connectivity and clusters between fields. It presents numerous findings about relative anonymity, fame, productivity, and the fields in which “scientists” were most implicated, but its principal interest is in proposing a method to sidestep modern observer’s categories.