On February 19, 2008, Professor of Law Lee Fennell presented the 2008 Coase Lecture on Law and Economics. Problems involving the aggregation and division of entitlements, she noted, are ubiquitous in law and in everyday life. Fragments held by multiple parties—such as parcels of land, effort, or segments of a bridge—often must be assembled together to be worth much. Conversely, a presently unified entitlement may be more valuable if it can be split into separate pieces held by different parties. The lecture examined these "lumping" and "slicing" problems (which turn out to be two sides of the same coin), showed how they turn up in both interpersonal and intrapersonal contexts, and offered some tools for addressing them.