There are many notions of property rights. The critical concept in this book is an Economic Property Right, which is defined as an individuals ability in expected terms to exercise a choice with respect to a commondity. Such rights depend on the individuals legal and moral rights to that commodity. Such rights are complicated because they might be spread out across different subsets of a commoditys attributes, and different people might hold different types of rights to the commodity. Furthermore, the strength of any given property right can vary and is under the choice of various people.