Delphine N. Conzelmann invites readers into the rich intellectual world of William of Saint-Thierry, a pivotal figure of the twelfth-century monastic reform. Bird of Many Plumes provides a comprehensive study of how William conceived and applied the notion of authority within his writings. As a Cistercian thinker, William’s work bridged the gap between theological tradition and the personal experience of the divine, and this book skillfully unpacks how he navigated the competing claims of scripture, ecclesiastical hierarchy, and mystical insight. By examining the diverse 'plumes' of authority in his work, Conzelmann illuminates William’s enduring significance for our understanding of medieval spirituality and institutional power. This meticulously researched volume is essential reading for historians and theologians alike, offering a nuanced portrait of a man who sought to balance the rigour of medieval scholarship with the warmth of contemplative love. Discover how his reflections on obedience and leadership can still speak to the challenges of modern spiritual authority.