William of Saint-Thierry (ca. 1080-1148) was a Benedictine abbot of the Abbey of Saint-Thierry and a close friend of Bernard of Clairvaux. Because of this friendship, toward the end of his life he became a Cistercian monk at Signy l'Abbaye in the Ardenne forest. Twenty-one of his writings extant today establish his enduring legacy as a distinguished theologian of Trinitarian doctrine, Christology, and contemplative prayer.

Thomas X. Davis, OCSO, has translated two works of William-The Mirror of Faith (1979) and The Nature and Dignity of Love (1981)-and published several articles on William and monastic subjects. He is the abbot emeritus of the Trappist-Cistercian Abbey of New Clairvaux.