The surreal and bizarre images which fill the religious works of the sixteenth century Dutch painter, Hieronymus Bosch, have long intrigued and defied explanation.Assembling a wealth of fascinating evidence from Western Europe, the Balkans and the Middle East, Lynda Harris argues that Bosch's work was intended to convey a double meaning. Outwardly his paintings were traditional enough to be accepted by his wealthy patrons and the Church authorities. But behind their appearance of orthodoxy, they portray the doctrines and attitudes of Catharism, the medieval gnostic and dualist heresy which affirmed that the earth was literally Hell, ruled over by Satan.In a detailed analysis of Bosch's symbolism, the author uncovers for the first time the hidden meanings of his great religious paintings. She provides a colourful description of the religious world at the end of the Middle Ages and shows how the early Gnostic inheritance was handed down in spite of frequent persecutions. She also reveals something of the transcendental vision of the divine realm of Light to which the Cathars clung faithfully as they went singing to their deaths in the fires of the Inquisition.