Focuses on the rich and varied visionary and mystical literature of the early, high and late Middle Ages, including the writings of Bernard of Clairvaux, Richard of St. Victor, Julian of Norwich, Margery Kempe, Richard Rolle, the author of the Cloud of Unknowing, and Meister Eckhart. The influence of early theologians and philosophers (such as Origen, Plotinus, and Augustine) on these mystics is considered in detail, as is the influence of the medieval mystics on mystical thinkers of Renaissance Europe (including Teresa of Avila and John of the Cross).