The possession theories of Grotius, Cumberland, Locke, Hume, Rousseau and Kant are detailed in pursuing the aim of making the authors' respective legal-philosophical conceptions, as such, understandable. It is correspondingly attempted: first, to expose the theory-tradition in which the conception is embodied; second, to demonstrate the coherence of the Possession theory with the remaining philosophical opinions of the author; and third, to reconstruct the ideas through which the author seeks to substantiate objectively, and free from ideology, his respective theory.