Ownership and economic behaviors are highly salient elements of the human social landscape. Indeed, the human world is literally constructed of property. Individuals perceive and manipulate a complex web of people and property that is largely invisible and abstract. In this chapter, the authors focus on drawing together information from a variety of disciplines, including legal theory, philosophy, psychology, and economics, to begin creating a coherent picture of the cognitive architecture that underlies ownership concepts. In doing so, the authors review theories of ownership and discuss recent research that highlights the unique contributions garnered by studying ownership in a developmental context. (Contains 1 footnote.)