Don Isaac Abravanel (1437 1508) was a major historical figure during the waning of the Middle Ages. Statesman, diplomat, courtier, and financier, he was, at the same time, a scholar of encyclopedic learning, a philosopher, an exegete, a prolific author, a mystic, and an apocalyptist. In Abravanel, B. Netanyahu suggests, two long lines of tradition met and concluded: that of medieval Jewish statesmen and that of medieval Jewish philosophers. In what is both a biography and an exploration of Abravanel's thought and influence, Netanyahu describes how Abravanel illuminated the grave crisis and...