This thesis is a study of Leibniz's concept of perception in relation with other fundamental components of his metaphysical system. The other components of Leibniz's metaphysics that are investigated are God, monads, unity, change, representation and interaction. Leibniz's system is largely determined by the idea of God and the relevant theories that are connected to this idea. That this world is the 'best of all possible worlds' and the 'system of pre-established harmony' are the theses that Leibniz deduces from the idea of God and of substance. The conception of substance is central in Leibniz's system. In Chapter Three, the concept of monad or substance is analyzed in detail. Leibniz's theories of truth, his conceptions of extension and ...