This volume is a revision of a second edition (1956) printed from transcribed lectures delivered by Dr. Tillich to seminary students. It complements his volume on Perspectives on Nineteenth and Twentieth Century Protestant Theology, and with that volume seeks to interpret classical Christian traditional thought. Tillich's purpose in this series of lectures was not to cover all variations in Christian thought, but to deal with those ideas which have become an accepted expression of the church--in a word, dogma. The organization of the lectures follows a simple chronological sequence, beginning with a survey of the circumstances that made the appearance of Christianity a movement fortunate in its time (kairos). But the author does not refrain from inserting his own judgments upon events and developments ("". . . and he was right in thinking so""); and he sees the story of Christian dogma as issuing at last in the concept that has been central to all of Tillich's thought--that of correlation. The oral sources of this volume give it a simplicity and directness of style which should make it accessible to a wide range of readers otherwise put off in much theological writing.