In Physical Realization, Sydney Shoemaker considers the question of how physicalism can be true: how can all facts about the world, including mental ones, be constituted by facts about the distribution in the world of physical properties? Physicalism requires that the mental properties of a person are 'realized in' the physical properties of that person, and that all instantiations of properties in macroscopic objects are realized in microphysical states ofaffairs. Shoemaker offers an account of both these sorts of realization, one which allows the realized properties to be causally efficacious. He also explores the implications of this account for a wide range of metaphysical issues, including the nature of persistence through time, the problem of materialconstitution, the possibility of emergent properties, and the nature of phenomenal consciousness.