Throughout the Middle Ages, John the Evangelist, identified as the author of both the Book of Revelation and the most profound and theologically informed of the four Gospels, provided monks and nuns with a figure of inspiration and an exemplar of vision and virginity. Rather than the historical apostle, this book's protagonist is a persona of the Evangelist established in theology, the liturgy, and devotional practice: the model mystic, who, by virtue of his penetrating insight, was seen as having become a mirror image of Christ. In St. John the Divine, Jeffrey Hamburger assembles a remarkable set of images from the ninth to the fifteenth century that identify the inspired Evangelist so closely with the deity that he appears as his living image and embodiment. Hamburger explores the ways these representations of St. John in the guise of Christ elucidate the significance of images as such in medieval theology and mysticism. Above all, he shows how these artworks, presented together for the first time, epitomize the relationship between the visible and the invisible: between ideas, however abstract, and the concrete images that medieval Christians confronted face-to-face.

Drawing on the idea that mankind is made in the image of God, the illuminated manuscripts that Hamburger discusses represent an extreme yet exemplary instance in the history of the Christian image. By inviting monastic viewers to look beyond the rhetoric of imitation and strive for full identification with the deity in whose likeness they were made, representations of John in the guise of Christ embody a peculiarly Christian concept of the image. Taking as their point of departure the opening chapter of John's Gospel, the images simultaneously articulate a theology and a theory of the image -- subjects on which most medieval texts remain silent. Hamburger investigates the concept and function of the Christian image as it is elaborated both in the images themselves and in commentary from Eriugena to Eckhart. In underscoring the vitality and complexity of the iconographic imagination, Hamburger's study reframes the relationship between medieval art and theology and underscores the indispensable place of images within medieval monasticism.