Paul O'Grady's study provides an in-depth analysis of Aquinas's contribution to the philosophy of religion. It begins by situating him within that discipline and potential objections to such an enterprise are examined. Aquinas's contexts are then discussed – historical, biographical and conceptual. Aquinas's views on philosophy and theology, and faith and reason are assessed. Three arguments for the existence of God are explored in detail – the argument from motion, the argument from contingency and the argument to design. His responses to the problem of evil and the challenge of naturalism are covered. His negative approach to God's nature is discussed, including his views on divine simplicity and eternity, which, it is argued, are distinctive and theoretically fruitful. Then his positive account of divine goodness, knowledge and power is explored, as well as the linguistic issues which arise from attempting to talk about God.