The Summa Theologica or simply the Summa) is the best-known work of Thomas Aquinas (c. 1225–1274). Although unfinished, the Summa is "one of the classics of the history of philosophy and one of the most influential works of Western literature."[1] It was intended as an instructional guide for moderate theologians and a compendium of all of the main theological teachings of the Catholic Church. It presents the reasoning for almost all points of Christian theology in the West. The Summa's topics follow a cycle: the existence of God; Creation, Man; Man's purpose; Christ; the Sacraments; and back to God. Among non-scholars, the Summa is perhaps most famous for its five arguments for the existence of God known as the "five ways" (Latin: quinque viae). The five ways occupy one-and-a-half pages of the Summa's approximately three thousand, five hundred pages.