Suppose, for reductio ad absurdum, that wholes are real.Then a whole is either numerically identical to or else numerically distinct from its collection of parts. Since numerically identical entities share all of their properties, and since a whole has the property of being a unity whereas a collection of parts has the property of being a multiplicity, a whole is not numerically identical to its collection of parts. But neither is the whole numerically distinct from this collection. For a whole and its collection of parts occupy the same space at the same time, and numerically distinct entities cannot do this: This is the Problem of the One over the Many. Hence, since a whole is neither identical to nor different from its collection of parts, wholes are not real. Pulling a cart’s handle suf?ces for pulling the cart itself. This provides evidence against the soundness of the preceding reductio argument. Indeed, this sort of evidence motivates the Nya¯ya-Vais’esika School’s thesis that two distinct entities can occupy the same space simultaneously, provided that there is an eternally existing inherence relation between the entities in virtue of which one contains the other. This thesis, however, is incompatible with Buddhism’s basic commitment to impermanence.Accordingly, most Indian Buddhists infer that wholes are unreal. Huayan Buddhists, in contrast, and in an attempt to accommodate the reality of wholes within a Buddhist framework, modify Nyaya-Vais’esika’s solution to the Problem of the One over the Many by arguing that the inherence relation between a whole and its collection of parts need not be eternal. The discussion to follow elaborates upon these various responses to the Problem of the One over the Many, in the service of two central goals. The first is to situate Huayan’s mereology within the context of Buddhism’s historical development, showing its continuity with a broader tradition of philosophizing about part–whole relations. The second goal is to highlight the way in which Huayan’s mereology combines the virtues of the Nyaya-Vais’esika and Indian Buddhist solutions to the Problem of the One over the Many while avoiding their vices.