During the later Middle Ages people became increasingly obsessed with vision, visual analogies and the possibility of visual error. In this book Dallas Denery addresses the question of what medieval men and women thought it meant to see themselves and others in relation to the world and to God. Exploring the writings of Roger Bacon, Duns Scotus, Peter Aureol and Nicholas of Autrecourt in light of an assortment of popular religious guides for preachers, confessors and penitents, including Peter of Limoges' Treatise on the Moral Eye, he illustrates how the question preoccupied medieval men and women on both an intellectual and practical level. This book offers a unique interdisciplinary examination of the interplay between religious life, perspectivist optics and theology. Denery presents significant new insights into the medieval psyche and conception of the self, ensuring that this book will appeal to historians of medieval science and those of medieval religious life and theology.