This book is an examination of the teaching of the Russian religious thinker Vladimir Solov'ev (1853-1900) about divine-humanity, the term he used to express the patristic doctrine of deification. The first chapter examines the theme of deification in the patristic tradition and shows that Solov'ev was extremely familiar with the writings of the Church Fathers and the doctrinal teachings of the early Church Councils. The following three chapters are devoted to specific works of Solov'ev which are in detail, Lectures on Divine Humanity, The Spiritual Foundations of Life and The Justification of the Good. Of these, the latter two have, to date, received little extended scholarly study. The over-arching thrust of this work is that Solov'ev's concept of deification started as a reflection of the mystical and cosmic expressions of deification characteristic of the late Greek patristic period but develops so to be expressed in the western terminology of grace and focuses on the active implementation of deification in the world, taking the teaching out of its original monastic context.