In 1341 in Aragon, a Jewish convert to Christianity was sentenced to death, only to be pulled from the burning stake and into a formal religious interrogation. His confession was as astonishing to his inquisitors as his brush with mortality is to us: the condemned man described a Jewish conspiracy to persuade recent converts to denounce their newfound Christian faith. His claims were corroborated by witnesses and became the catalyst for a series of trials that unfolded over the course of the next twenty months. Between Christian and Jew closely analyzes these events, which Paola Tartakoff...