Among the casualties of the western intervention in Iraq and the recent activities of ISIS are the Mandaeans of southern Iraq. Keepers of an ancient minority religious tradition, these peace-loving people may now be found in small numbers in such unlikely locations as Sydney, New Jersey, or Manchester. They have a claim to being the last Gnostics, The Mandaeans place weekly river baptisms at the centre of their religious life, and the primary exemplar, though not the founder, of their religion is claimed to be none other than John the Baptist. Could this really be true? Could an obscure middle-eastern ethnic religion really stretch all the way back to the Gnostics and John the Baptist?What is the real history of this mysterious and long-lived sect. What is their relationship to other ancient minority religions such as the Yazidis and Druze? Could they have influenced the Knights Templar? Do they preserve traces of ancient Babylonian religion? Could they really have a link with John the Baptist, and who was that mysterious figure? Was Jesus himself an apostate Mandaean?