St. Thomas Aquinas

1225-1274.  Italian Priest of the Dominican religious order (O.P.) and Doctor of the Church.  His staggeringly large output represents the summit of scholastic philosophy and theology, which has been designated as the primary Catholic philosophy and theology by the tradition of the Church, and by the explicit pronouncements of modern popes, particularly Leo XIII and St. Pius X.  St. Thomas’s Summa Theologiae is an enormous compendium of Christian theology distilled from the works of the Fathers and Doctors of the Church before him, written in the philosophical terminology of Aristotle.  It is the primary textbook for the training of priests.  Excellent books on St. Thomas are the biography St. Thomas Aquinas by G.K. Chesterton and the Summa of the Summa by Peter Kreeft (an abbreviated, annotated edition of the Summa Theologiae).  Both are published by Ignatius Press.