This short and accessible book introduces readers to the problems of heresy, schism and dissidence over the last two millennia. The heresies under discussion range from Gnosticism, influential in the early Christian period, right through to modern sects. The idea of a heretic conjures up many images, from the martyrs prepared to die for their beliefs, through to sects with bizarre practices. This book provides a remarkable insight into the fraught history of heresy, showing how the Church came to insist on orthodoxy when threatened by alternative ideals, exploring the social and political conditions under which heretics were created, and how those involved were 'tested' and punished, often by imprisonment and burning. Engaging written, A Brief History of Heresy is enlivened throughout with fascinating examples of individuals and movements. A short, accessible history of heresy. Spans the last two millennia, from the Gnostics through to modern sects. Considers heresy in relation to ecclesial separatism, doctrinal disagreement, church order, and basic metaphysics. Enlivened with intriguing examples of individuals and movements. Written by a leading academic in the field of Religious History.