This book reconstructs and critically assesses the theories of property developed by Kant, Fichte, Hegel and Marx. It aims to clarify how these philosophers understood the concept of property and to explain their different views concerning the specific form that this concept ought to have in society. I emphasize how in the writings of these philosophers the idea of a pre-social and pre-political right to property is undermined by how social recognition forms a constitutive moment of the concept of property. Any account of how the concept of property is instantiated in specific property rights or forms of property must therefore accommodate this moment of social recognition. Kant, Fichte, Hegel and Marx are shown to provide different accounts of how this is achieved. Each time, however, the specific form of property is shown to be justified in terms of the same idea and value, namely freedom.