But the interest attaching to the City of God is not merely historical. It is the earnestness and ability with which he developes his own philosophical and theological views which gradually fascinate the reader, and make him see why the world has set this among the few greatest books of all time. The fundamental lines of the Augustinian theology are here laid down in a comprehensive and interesting form. Never was thought so abstract expressed in language so popular. He handles metaphysical problems with the unembarrassed ease of Plato, with all Cicero's accuracy and acuteness, and more than Cicero's profundity. He is never more at home than when exposing the incompetency of Neoplatonism, or demonstrating the harmony of Christian doctrine and true philosophy. And though there are in the City of God, as in all ancient books, things that seem to us childish and barren, there are also the most surprising anticipations of modern speculation. There is an earnest grappling with those problems which are continually re-opened because they underlie man's relation to God and the spiritual world,—the problems which are not peculiar to any one century. As we read these animated discussions,