Beauty and ugliness, two extremes that intersect through human experience, remain an inexhaustible source of creative inspiration and popular belief. In 'The Beauty of Ugliness and the Ugliness of Beauty: Materializing Monstrosity in the Middle Ages,' the editors aim to redefine the concept of the medieval monster by revisiting issues that have received little attention. This collection of five essays examines various topics, including the stigmatization of disability in clerical circles through canon law decretals, the duality of good and evil in the Latin world, the image of women in marriage contract negotiations, the interpretation of monsters as 'signs' or 'things,' and the evolving interpretations of medieval monsters in post-medieval contexts.