One of the great philosophers of the 20th Century, Josef Pieper, gives a penetrating introduction and guide to the life and works of perhaps the greatest philosopher ever, St. Thomas Aquinas. Pieper provides a biography of Aquinas, an overview of the 13th century he lived in, and a wonderful synthesis of his vast writings. Pieper shows how Aquinas reconciled the pragmatic thought of Aristotle with the Church, proving that realistic knowledge need not preclude belief in the spiritual realities of religion. According to Pieper, the marriage of faith and reason proposed by Aquinas in his great synthesis of a theologically founded worldliness was not merely one solution among many, but the great principle expressing the essence of the Christian West. Pieper reveals his extraordinary command of original sources and excellent secondary materials as he illuminates the thought of the great intellectual Doctor of the Church.