 One can find discussions of parts and wholes throughout the medieval philosophical and theological literature. But there are two places where the student of medieval mereology can reliably look to find sustained reflections on parts and wholes as such, namely, treatments of division and the Topics. The main authority on division and the Topics is the Roman philosopher  Boethius  (c. 480–524 C.E.). Boethius is now most famous for his Consolation of Philosophy, but his influence on medieval philosophy is as much due to his commentaries on Aristotle’s Categories and On Interpretation, his theological treatises, and his handbooks on logic (see Chadwick 1981 and Marenbon 2003). Boethius’ treatment of division is found in his handbook On Division (De divisione). His treatment of the Topics is found in his handbook On the Topical Differences (De differentiis topicis) and in his commentary on Cicero’s treatment of the Topics (In Ciceronis Topica).