Rabbi Levi ben Gershom (Ralbag, Gersonides; 1288-1344), one of medieval Judaism's most original thinkers, wrote about such diverse subjects as astronomy, mathematics, Bible commentary, philosophical theology, "technical" philosophy, logic, Halakhah, and even satire. In his view, however, all these subjects were united as part of the Torah. Influenced profoundly by Maimonides, Gersonides nevertheless exercised greater rigor than Maimonides in interpreting the Torah in light of contemporary science, was more conservative in his understanding of the nature of the Torah's commandments, and was...