The conceptual dimensions of property and property rights have many practical implications for resource allocation. Economic analyses as a rule take property rights for granted. Certainly, as far as the relevance of the theory of ownership to efficient resource allocation is concerned, there is much less of a consistent, self-contained, and comprehensive body of analytical insights than is the case with many other central topics of economics (Yarrow 1989, pp. 52ff.). As an economist I, therefore, have to borrow some notions of property and property rights from other disciplines. Contemporary philosophical, moral, and legal discourses (Munzer 1990, pp. 23-25) generally stipulate property rights as a somewhat narrower concept than property per se. The latter includes negative rights as well, that is, property rights that belong to those who are not ultimate owners. But I believe little will be lost by sidestepping this fine-tuning here. I shall mostly refer to property rights, in any case.