In 1631, at the epicenter of the worst excesses of the European witch-hunts, Friedrich Spee, a Jesuit priest, published the Cautio Criminalis, a book speaking out against the trials that were sending thousands of innocent people to gruesome deaths. Spee, who had himself ministered to women accused of witchcraft in Germany, had witnessed firsthand the twisted logic and brutal torture used by judges and inquisitors. Combined, these harsh prosecutorial measures led inevitably not only to a confession but to denunciations of supposed accomplices, spreading the circle of torture and execution...