This is the second volume of a detailed and systematic exposition of the history, canonical structure, doctrine, moral and social teaching, liturgical services, and spiritual life of the Orthodox Church. The purpose of this series is to present Orthodox Christianity as an integrated theological and liturgical system, in which all elements are interconnected. Theology finds its expression and is shaped in the liturgical experience and church art-including icons, singing, and architecture. The services, in their turn, influence the ascetic practice and the personal piety of each Christian; they shape the moral and social teaching of the Church as well as its relation to other Christian confessions, non-Christian religions, and the secular world. The first volume provided an account of the historical arc of the Orthodox Church during the first ten centuries after Christ's nativity, then examined the canonical structure of the Orthodox Church. This volume examines the sources of Orthodox doctrine in Scripture and Tradition; its teaching on God in Trinity and Unity, in his essence and in his energies; on the world and man; on Jesus Christ, the incarnate God; on the Church, the body of Christ; on the Theotokos, Mary; and on eschatology, the last things.