A comprehensive study of one of the darkest phenomena in the history of mankind - the Inquisition, which in Spain reached an extreme degree of cruelty. The author examines the political, historical, religious and economic background of the emergence and spread of the Inquisition, gives vivid psychological portraits of both the organizers of this sinister institution, who fanatically believed in its sanctity, and their spiritual opponents, who ended their lives in the flames of the fires.