R.I. Moore traces the roots of dissent, the support which it commanded, and the reactions which it elicted from the holders of established power in the changing needs and conflicts of the expanding society of the eleventh and twelfth centuries: in spite of repression religious uniformity has never since reigned unchallenged. His controversial argument is that the ideas and aspirations of the heretics had far less to do with religious faith or outlook than with the consequences of social anxieties and frustrations. He holds too that similarly the dogma of the Catholic Church can be understood more clearly in terms of the politics of power than of salvation. Originally published by Allen Lane, 1985.