Professor Jacob Katz (1904-1998) was one of the giants of Jewish scholarship in the 20th century. There is virtually no aspect of Asheknazic Jewish life in the medieval and modern periods that Katz didn’t illuminate with his prodigious output. From the origins of Jewish assimilation to the history of halakhah, Jewish-Christian relations, halakhah and kabbalah, antisemitism, Jewish emancipation, religious reforms, Jewish nationalism, and on to the emergence of Orthodoxy, Katz’s massive learning and broad disciplinary scope forever changed the way scholars think about all these matters. Jacob Katz on the Origins of Orthodoxy presents leading research on Professor Jacob Katz to reflect on his legacy nearly twenty-five years after his passing, and reprints some of his landmark essays, and also introduces English readers to a series of never-before-published interviews conducted with Professor Jacob Katz over several decades.