Abstract: This book stems from the international conference held in Sarlat in 2008, dedicated to the theme of custom and its manifestations, specifically in relation to La Boétie’s Discours de la Servitude volontaire. Studying custom in the context of Renaissance humanism, as well as its ancient and medieval roots through to its modern developments, the philosophers, jurists, historians, and literary scholars assembled in this volume seek to assess the epistemological and ethical ambivalence of custom, between “second nature” and denaturation.