In this book, Fulton Sheen addresses what G. K. Chesterton called "the most tremendous question in the world; perhaps the only question in the world:" how man, through the power of reason, can know the nature of God. Tracing the course of philosophy from the Middle Ages to modern times, he shows Thomistic realism to be an adequate response to modern ideals. Emphasizing reason as a way of attaining knowledge of God, Bishop Sheen identifies the current age of agnosticism with its simultaneous distrust of reason. In a lucid tone, he analyzes the modern attack on intelligence, while presenting Scholastic philosophy as the solution to modern problems. Bishop Sheen succeeds in actualizing St. Thomas to such a degree that he ends up proving that Scholastic philosophy speaks to the world today as freshly as it did to the world of the 13th century. Catholics will appreciate the book as an astute criticism of modern theory and coherent introduction to St. Thomas, while non-Catholics will find it useful for its strict reliance on reason and not dogma in the pursuit of philosophical knowledge.