The masks of Reims Cathedral are among the best sculptural achievements of 13th century Europe. The faces with expressive mimicry are in striking contrast to the rest of the monumental sculpture of Notre-Dame de Reims. The author carries out detailed formal analyses, devotes herself to the meaning and function of the “masks” in the context of the cathedral and compiles ancient as well as Romanesque source models. Making use of an interdisciplinary approach, the intellectual and historical currents of the times are taken into consideration; including, for example, medieval moral theology and philosophy up to Thomas Aquinas, as well as literature, medicine and social history. The extensive catalogue and the numerous pictorial comparisons make possible a summary of the physiognomical variety and pathognomonic peculiarity of the masks of Reims, making this monograph into a standard work on the research of Gothic sculpture.