Eric Claeys’s book, Natural Property Rights, introduces a Lockean-based theory of interest-based natural property rights. Central to Claeys’s theory are the concepts of justified interests and productive use. A justified interest, Claeys writes, exists when an individual demonstrates a stronger interest in a resource than anyone else in the community and uses the resource productively in a manner that is “intelligent, purposeful, value-creating, . . . sociable,” and leads to survival or flourishing. Claeys’s theory demonstrates “how a standard justification for property gets implemented in practice” and how a community’s “goods” build on the individual’s goods. 
 Claeys’s community “goods” focus, however, is antithetical to a Lockean private property ownership theory, which prioritizes an individual’s interest, except for the provisos—no waste and enough and as good. Although Claeys adequately addresses the differences between his and Locke’s theories, Claeys’s regard for both community and individual interests causes one to question whether his theory is truly Lockean-based.
 Claeys’s book consists of four parts: Natural Law and Natural Rights (Part I), Property’s Foundations (Part II), Property Law (Part III), and Property in Law and Policy Generally (Part IV). This Article addresses Parts I and II and explores the defenses and justification for Claeys’s interest-based natural property rights theory under a Lockean framework. 
 This Article also addresses the defects in a Lockean natural rights theory, including Claeys’s application of that theory. Locke’s theory focuses on the natural rights of a specific community. Such a focus often disfavors people situated in out-of-power positions, for example, a land ownership dispute between indigenous people and recent immigrants that have organized themselves under laws that do not recognize the existing rights (natural or otherwise) of the indigenous people. Yet, both Claeys and Locke contend that natural rights emanate from a divine source (God) that intended humankind to use the things of nature for its survival and flourishing. But, when fundamentally different views exist concerning a resource’s ownership or productive use, rights conflicts arise. These conflicts often result in one community’s natural rights trampling another’s. This Article introduces a balancing interest test as a possible resolution to this conflict. The proposed balancing interest test seeks to maximize the common good in the most equitable way by finding an equitable mean between conflicting interests. Finally, this Article explores whether Claeys’s theory can justify natural property rights in intellectual property, specifically patents.