Common property economics defines and clarifies the theoretical distinction between open access and common property and empirically tests the adequacy of resource allocation under common property and empirically tests the property in comparison with private property. Group use of natural resources has often received the blame for overexploitation and mismanagement, whether of fisheries, grazing land, oil and gas pools, groundwater, or wildlife. In this book two types of group use are identified: open access and utilization without any controls on extraction rates, a situation in which resource overexploitation often occurs. In contrast, common property refers to the situation where the group controls the access to and extraction rates of the resource. The common property solutions differ from those associated with open access. The nonoptimality of open access is demonstrated with graphic, game theoretic, and mathematical models. The necessary and sufficient conditions for common property to overcome the difficulties of open access are examined. Stevenson discusses historical examples, the basis in legal concepts, the contrast with public goods, the formation, and the stability of common property. In a detailed, empirical study of alpine grazing in Switzerland, the author compares the performance of common property with that of private property. He also notes the similarity in structure between the Swiss grazing commons and the English open field system.