Property in Activities is a distinct and integrated property-concept applying directly, not to things, but to actions. It describes a determite ethico-political relation to a particular activity - a relation that may (but equally may not) subsequently effect a wide variety of relations to some thing. Property in Activities illumites many of the vexing problem cases in property theory, including commul, intangible, fugacious, hunting, fishing, customary and recreation property rights. The same is true of property in various sectors of law, in philosophical arguments such as Locke's, and in historical usage prior to the nineteenth century. By illustrating how one stable concept can resolve this myriad of otherwise puzzling cases, I argue that Property in Activities is as important a concept as Ownership of Things.