One of the outstanding Christian thinkers of all time, Maximus the Confessor (ca. 580-662) exerted a powerful formative influence on the Church when it was still one and undivided. Maximus left his stamp on Christianity as it is now recognized by all three broad streams of Christian faith: Eastern Orthodox, Roman Catholic, and Protestant. Yet for centuries the detailed study of Maximus's writings was neglected. The first edition of Thunberg's Microcosm and Mediator (1965) helped to transform this situation of indifference into one of intense interest in Maximus and the subtleties of his thinking. This new edition has been revised and expanded, with updated references and bibliographies. The focus of Microcosm and Mediator is Maximus's anthropology, his highly developed general reflections on human nature. Maximus understands man as, not only a being - a microcosm - who reflects the constitution of the created universe, but also as a being - a mediator - created in the image of God, whose task it is, in Christ, to reconcile the spiritual and the sensible into one homogeneous unity.