Anselm's ontological argument is one of the most fascinating, most controversial, and most misunderstood arguments in the entire history of Western thought. By centring the argument firmly in the Neoplatonic tradition within which Anselm was writing, Understanding Anselm's Ontological Argument sheds fresh light and clarity on this enigmatic piece of philosophy. It argues that, far from resting upon a fallacy or illegitimately attempting to define God into existence, Anselm's argument is a powerful and plausible philosophical proof, and deserves to be taken seriously as such. Written to be understandable for specialists and non-specialists alike, U nderstanding Anselm's Ontological Argument is ideal for scholars and researchers in philosophy of religionand philosophy in the Middle Ages (especially Neoplatonism) as well as for medievalists in general. Guy Jackson was born and raised in Norfolk, England. He studied Classics at Oxford and Theology at Cambridge. Understanding Anselm's Ontological Argument is his second book.