Although John Locke’s theory of appropriation is undoubtedly influential, no one seems to agree about exactly what he was trying to say. It is unlikely that someone will write the interpretation that effectively ends the controversy. Instead of trying to find the one definitive interpretation of Locke’s property theory, this article attempts to identify the range of reasonable interpretations and extensions of Lockean property theory that exist in the contemporary literature with an emphasis on his argument for unilateral appropriation. It (...) goes through Locke’s argument point-by-point discussing the controversy over what he said and over what he perhaps should have said to make the most valuable and coherent argument. The result is an outline of Lockean theories of property: a menu of options by which one might use appropriation to justify property rights. Supporters only need to pick the version they find most plausible, but opponents should be aware of the entire menu. Anyone claiming to refute appropriation-based property rights must address not only one but all potentially valid versions of it. (shrink)