With this provocative book the name of Fulton J. Sheen burst upon the literary world in 1925.It was a dramatic debut, for in this profound work he hurled the challenge at modern thinkers on the very ground they always assume is their own: the area oi human reason. Bishop Sheen indicts modern philosophy for having lost faith in man's intellect, and therefore for having abandoned hope of attaining any knowledge of God by rational means, He traces the decline of philosophy from the serene height of the high Middle Ages to its present muddle, contrasting the balanced realism of St. Thomas Aquinas with modern philosophy's distrust of reason and showing how this affects man's idea of God, Thomism, the author demonstrates, stoutly affirms the validity of human knowledge and proves-by reason alone, not by revelation-the exi5tencd of God and many of His attributed. But modern thought, in its headlong flight reason denies the possibility of man attaining rational knowledge. It thus leaves man two alternatives, neither adequate for questing minds: agnosticism, or a religious belief based on emotional need or blind faith.