The Summa Theologica (Latin: "Summary of Theology" or "Highest Theology") is the most famous work of Thomas Aquinas (1225–1274). It was intended as a manual for beginners as a compilation of all of the main theological teachings of the time. It summarizes the reasoning of all points of Christian theology, which before the Protestant Reformation subsisted solely in the Roman Catholic Church. The Summa's topics follow a cycle: the existence of God; God's creation, Man; Man's purpose; Christ; the Sacraments; and back to God. It is famous for its five arguments for the existence of God, the Quinquae viae (Latin: five ways). Throughout his work, Aquinas cites Augustine of Hippo, Aristotle, and other Christian, Jewish, Muslim and ancient pagan scholars.

This is an electronic edition of the complete book and includes an author biography. This book features a table of contents linked to every chapter.