Deviations and separatist movements are endemic to all religions and from the beginning Christianity experienced them in the shape of the early heresies. In the West unity was preserved until the first half of the sixteenth century, when it was destroyed by Protestantism. Protestantism itself broke up into a multitude of sects-a process that has continued and is still going on at the present day, so that there and now upwards of 260 independent Protestant Churches and sects. In this book Mgr. Konrad Algermissen, defining a modern sect as an individualistic religious community characterized by the Donatist concept of special election, a religious ethical code, fundamentalism, religious fanaticism and powerful propaganda activity, deals with six principal bodies together with some of their offshoots, whose adherents total in all about 12,000,000.