In this work, one of Sheed's more popular titles, he defines sanity as living mentally in the real world. He argues that some of the more important elements of reality cannot be known save through theology. This book contains as much theology as one must know to be at home and aware in the real world. The first section treats of God as the human mind might discover him, as He has revealed Himself. The second section treats of the universe God made-particularly humanity and what has happened to it. The third section considers what the life of man should be.