Property rights have long been associated with a simple and distinctive technology: exclusion. But technologies can become outdated as conditions change, and exclusion is no exception. Recent decades have featured profound changes that have made exclusion a less useful, less necessary, and more expensive way of regulating access to resources. This Article surveys the prospects for a post-exclusion understanding of real and personal property. It proceeds from the premise that property is built upon complementarities, the nature and scale of which have undergone seismic shifts. Physical boundaries and lengthy claims on resources are designed to group complementary elements together in time and space in order to generate value. But many of the most important complementarities are now found not within a given owner’s holdings but among the holdings of different owners. Moreover, as slices of on-demand access increasingly replace lumpy long-term possessory interests, the presumed strong complementarity associated with temporal continuity and spatial contiguity begins to break down. This Article shows how these trends have made property lines an increasingly poor mechanism for grouping together complements. It then considers how property rights might move beyond exclusion, and addresses some implications and objections.