Anselm of Canterbury (1033-1109) was one of the originators of medievil scholastic philosophy. This collection of his best-known philosophical works contains, among other things, the Proslogium, in which Anselm first put forward the famous ontological argument for the existence of God. Also included are Gaunilo of Maurmoutier's criticism of Anselm's argument and Anselm's reply to Gaunilo.
