ELIYYAHU BEN SHELOMOH ZALMAN (1720–1797), known as the Vilna Gaon, was a scholar and theologian. Born in Selets, Lithuania, to a family renowned for its Talmudic erudition, Eliyyahu became one of the major intellectual and spiritual figures in Judaism, the preeminent representative of rabbinism in the eighteenth century. At an early age he displayed both a prodigious memory and a striking aptitude for analysis, which he applied to all branches of Jewish learning—the Torah, Mishnah, Talmud, Midrash, rabbinic codes, and Qabbalah. As a youth, his authoritative knowledge was acknowledged throughout Ashkenazic Jewry, and he soon became known simply as "the Gaon," the genius (an honorific title not to be confused with the title of the heads of the Babylonian yeshivot a thousand years earlier). After his marriage and a tour of the Jewish communities of Poland and Germany, Eliyyahu settled in Vilnius...