The study of the monsters represents a preferential access to the imagery, the mentality, and to the religious beliefs of a given culture. Starting from this assumption, Ariel Toaff searches into an unknown and rare literature, through fantasy texts and travel reports, precepts and medicine handbooks and brings to light the marvellous or hideous fruits of the Jewish imagery in the Middle Ages and the Renaissance, together with some negative and caricatured descriptions of the Jews given at the beginning of the modern era. The title of the book refers therefore either to the imaginary monsters which can be found in ancient Hebraic culture or to the "monstrous" characteristics ascribed to the Jews from the Christians.

Ariel Toaff teaches Medieval and Renaissance History at Bar-Ilan University in Israel.