The bizarre and fantastic paintings of the Dutch artist Hieronymus Bosch have puzzled and intrigued their viewers for centuries. Following years of research which have taken her to every corner of Europe, Lynda Harris offers surprising new insights into Bosch's detailed and cryptic visual fantasies. Drawing on a wide variety of new sources, she deciphers Bosch's symbolism as the hidden expression of his heretical religious beliefs. She argues that Bosch belonged to the Cathar faith, a Manichean religious heresy which was persecuted and driven underground by the Church in the Middle Ages. This fabulously illustrated study reveals that while Bosch was carrying out commissions for his wealthy Catholic patrons, he was all the while coding his own inner heretical convictions in the hidden meanings of his paintings, as a record for posterity of the beliefs of his threatened religious sect.