In the 10th century, Rabbi Saadia Gaon, the leader of the rabbinic academy in Sura, Babylon, laid out the appropriate approaches to scriptural interpretation in his Book of Beliefs and Opinions. To arrive at the truth of religion, he declared, seekers are “obliged at once” to accept evidence verified by the testimony of their senses and/or authenticated by “reliable tradition.”For many, Saadia added, rational inquiries “may take a long time before they are completed, but that should not worry us; no one prevented by any hindrance from pursuing his investigations is left without religious guidance.”In the centuries before and after Saadia published his immensely influential work, Martin Goodman reminds us, Jews discussed, deployed and dismissed one or more of these methods as they tried to comprehend, conform to, and critique the central tenets of one of civilization’s oldest religions.In A History of Judaism, Goodman, a professor of Jewish studies at Oxford University, and the author of Rome and Jerusalem: A Clash of Civilizations, provides a monumental and magnificent, erudite and elegant account of the evolution of Jewish beliefs and practices over more than 3,000 years.Goodman makes superb use of existing sources – and is refreshingly candid about their limitations. He presents lively and informative portraits of dozens of (well-known and heretofore obscure) rabbis, rebels, mystics and self-proclaimed messiahs.He follows Jews from the Middle East across the globe, to Western and then Eastern Europe; China; India; the United States; and the State of Israel. And, among a host of topics, he examines the impact on Judaism of Christianity and Islam; the destruction of the Temple in 70 CE; traditions of dispute in the Middle Ages; the Kabbala; the Enlightenment; Zionism; Hassidism; the Holocaust; secularization and rates of intermarriage.GOODMAN EMPHASIZES the “variegated landscape” of Judaism – and resistance to codification and conformity. Although stopping work on the Sabbath was a widely recognized Jewish practice in the Mediterranean world, for example, disputes erupted about whether Jews should defend themselves if attacked on the day of rest. Essenes interpreted the taboo strictly, refusing even to venture outside their dwellings to defecate, while tannaim observed a “Sabbath limit” of 2,000 cubits, within which they were permitted to carry objects. In our own time, Goodman reminds us, the use of electricity on Saturday, and driving cars to attend synagogue services, “at times became fault lines between Jewish religious groups.” The absence of a powerful, centralized hierarchal institutional structure and the realities associated with the Diaspora clearly contributed to Judaism’s variegated landscape. Even as the reputation of rabbis spread to distant places, Goodman indicates, local autonomy prevailed. While French and German Jews accepted a ban on polygamy in ancient times, Jews in Islamic lands did not. In the 13th century, some French Jews read the Torah bareheaded. Sephardim and Ashkenazim used different liturgical practices, Hebrew pronunciation, prayers, poems and folk customs.That said, Goodman points out as well that variety, innovation and change did not go unchallenged. He points to the Hatam Sofer, a rabbi in Pressburg, Hungary, for 33 years, and his descendants (who reestablished their yeshiva in Jerusalem in 1950) as exemplars of the Orthodox response to Enlightenment modernity. Adopting a credo that any innovation can be banned because it is an innovation, the Sofers proclaimed: “Do not change your name, language or clothing to imitate the ways of gentiles. The women should read books in Yiddish, printed in our traditional font and based on the tales of our sages, and nothing else.... Do not say that times have changed, for we have an old Father, blessed be He, who has not changed and will never change.”These days, Goodman implies, more and more Jews locate themselves on either end of the religious spectrum. Many Diaspora Jews attribute their identity to their culture or ethnicity rather than their religion, and often marry non-Jews. In Israel, many secular Jews resent social welfare payments to large families, in which the father is deemed too devoted to talmudic studies to earn a living. Meanwhile, amid a search for spirituality and a return to tradition, the number of Orthodox Jews and Hassidim continues to grow. And, according to Goodman, Conservative Judaism is in crisis, “as congregants abandon the center ground it represents.”Surprising developments in the 20th century, Goodman notes, suggest caution about predictions for the 21st. After all, plausible arguments can be made that Judaism will flourish and that it will flounder. And so Goodman ends his splendid book where he began, with Josephus, the first century CE historian.Reluctant to interpret Daniel’s vision of the four empires to his Greek and Roman readers, Josephus rejoiced that he was expected only “to write of what is past and done and not of what is to be.” The writer is the Thomas and Dorothy Litwin professor of American studies at Cornell University.