Summa Theologica - Complete & Unabridged

The Summa Theologiæ (written 1265–1274 and also known as the Summa Theologica or simply the Summa) is the best-known work of Thomas Aquinas.
The Summa's topics follow a cycle: the existence of God; Creation, Man; Man's purpose; Christ; the Sacraments; and back to God.