In this book, Umberto Eco addresses the phenomenon of the ugly, which was most often considered as the opposite of the beautiful, but has never been studied in detail. However, ugliness is a much more complex concept than the simple negation of various forms of beauty. Does ugliness always symbolize evil? Why, for many centuries, philosophers, artists, writers have invariably turned to deviations from the norm, disproportions, depicting the machinations of the devil, the horrors of the underworld, the suffering of martyrs and the tragedy of the Last Judgment? What did they want to say with their works? How did contemporaries react to them and how do we perceive these works today?