Saints et diables au chapeau is a French monograph that explores the iconography and cultural significance of religious medals and pilgrim badges from the Middle Ages. Drawing on a rich collection of artifacts, the book examines how saints and devils were depicted on hats and other wearable items, shedding light on the interplay between faith, art, and everyday life in Western Europe between 500 and 1500. Through detailed illustrations and scholarly commentary, Denis Bruna traces the evolution of these devotional objects, their symbolic meanings, and their role in the broader context of medieval Christian art and symbolism. The work offers a valuable resource for historians, art historians, and collectors interested in medieval jewelry, leadwork, and the visual language of piety.