Although the Catholic Church today tolerates beliefs and religious practices at odds with its own, for several centuries it enforced its doctrine with threats, excommunication, banishment, imprisonment, seizure of lands, torture, and death. This book explains the origins of the Roman Catholic Inquisition in the 13th century, the expansion of the movement, its campaign against Jews in Spain, its response to the Reformation, and its eventual relaxation as a brutal instrument of the Church against perceived heresy.