Professor Evans is concerned here with those parts of the corpus Leontianum in which the sixth-century theologian expounded his doctrine on the person and nature of Christ, that is, in some chapters of the Contra Nestorianos et Euthychianos. The author argues that Leontius was an Origenist whose Christology derived from that of Evagrius of Pontus, and in the final chapter, which deals with Leontius’s life, undertakes to prove that Leontius the theologian is to be identified with Leontius the monk, a former disciple of Saint Sabas who was attacked as an Origenist by Cyril at Scythopolis; and, moreover, with Leontius apocrisiarius of the Council of 536, who played an important part in the controversy between the Orthodox and the Monophysites.