Exploring the relationship of heresy, dissent and society in the 12th and 13th centuries, The Devil's World shows how people made conscious choices between heresy and orthodoxy in the middle ages and were not afraid to exert their power as 'consumers' of religion. The book gives an account of all popular religious movements, looks at the threat that heresy presented to the Church and lay powers and considers the measures they took to deal with it. This new edition brings the historiographical debate right up to date including the work of R.I. Moore and Mark Pegg as well as extended sections on the Bogomil connection and women. Ideal for students of medieval and religious history.