This fundamental study marks a milestone in the history of research on the monstrous in the Middle Ages and on Western ways of thinking. I can state without hesitation that Williams has produced a magnum opus on this subject, with a highly personal approach, providing an overview of all previous works on the monster and the philosophical, theological, aesthetic, and literary context. His vision is at once encyclopedic, critical, and completely fresh ... This is clearly the work of a researcher in full maturity. Its many qualities place it in the front rank.Claude-Claire Kappler, Centre National de la Recherche Scientifique (CNRS), Paris