Summa Theologica

The Summa Theologica (or the Summa Theologiae or
simply the Summa, written 1265–1274) is the most famous work of
Thomas Aquinas (c. 1225–1274) although it was never finished. It was intended as
a manual for beginners as a compilation of all of the main theological teachings
of that time. It summarizes the reasonings for almost all points of Christian
theology in the West, 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, Aristotle, and other Christian, Jewish and even Muslim and
ancient pagan scholars.

The Summa Theologica is a more mature and structured version of
Aquinas's earlier Summa Contra Gentiles. This earlier work was more
apologetic, each article refuting a belief of a heresy.

-- Excerpted from Wikipedia, the free encyclopedia.