In early modern Europe, justice was always the key to public order and the state's main pillar. The pope, though the head of the church, was also a prince like any other, but his justice, as machinery and moral model, displayed the double nature of his rule, targeting not only actions but also beliefs and consciences. Irene Fosi, the doyenne of scholars of papal justice, lays out the ambitious, complex, and sometimes baffled endeavors of the pope's magistrates and through lively anecdotes gives the flavor of the encounter between the pope's assorted magistrates, inquisitors, and others, and...