Caird presents an outline of Greek philosophy, discusses its influence on the development of theology, and addresses the question of the genesis of Platonic philosophy in its logical, ethical, metaphysical, and theological aspects. He also presents an account of the theoretical and practical philosophy of Aristotle and of the Stoics. After initial discussion on the development of religion and its relation to theology, Caird focuses on the central idea of religion, and on the opposition of the secular and the religious consciousness. In the course of this exposition he attends to the characteristics of the philosophical theology of Greece, the theology of the early Christian and medieval periods, and the philosophy of religion more generally. Thereafter he examines in detail the precursors of Plato and the Platonic idealism from its earliest expression, with particular attention paid to Plato's theory of ideas, the systematic unity of Platonic ideas, and the concepts of God and human immortality. Following a discussion on the transition from Plato to Aristotle, Caird expounds Aristotle's positions on reason both in its theoretical employment and in its practical, and he closes with a discussion of Aristotle's exaltation of pure contemplation and Kant's exaltation of practical reason. Reflection on these matters leads Caird finally to the question of whether it is theoretical or practical reason that has primacy.