Neither Nor.

Common Prayers: Faith, Family, and a Christian's Journey Through the Jewish Year, by Harvey Cox (Houghton Mifflin, 305 pp., $24)

Harvey Cox is not afraid to reinvent himself. In 1965, the Harvard Divinity School professor published The Secular City, in which he predicted, if not the death of God, then at least the death of traditional religion. In 1984, religion was making something of a comeback, and so-like any fortune-teller worth his tea leaves-Cox tried a little reinterpretation. In his second major work, Religion in the Secular City, he examined two of the movements he judged responsible for this revival-fundamentalism and liberation theology. Not surprisingly, given his own leftist political orientation, he predicted the failure of the former and the success of the latter. He had once again bet on the wrong horse: Fundamentalism today is vigorous, and liberation theology is on the wane.

Undeterred, Cox is back. His new book, Common Prayers, barely mentions secularism, let alone liberation theology. Rather, it describes the author's personal return to traditional religion, albeit not his own. As Cox tells it, about 15 years ago he entered into his second marriage, this time to a Jewish woman, with whom he has one child, Nicholas. Before Nicholas was born, the two decided that he would be raised in the Jewish tradition. Since then Cox has learned a great deal about Judaism, and he summarizes his findings here in an eminently readable form.

The book's subtitle hints at its useful structure. Explaining Judaism, a religion of practices and rituals, through its calendar is probably the way that most Jews would do it. Beginning with the Sabbath, which Cox calls his favorite holiday, and traveling through the Jewish New Year, Passover, and Israeli Independence Day (to name a few), he explains not only the origins of each of the Jewish holy days and festivals, but also how they are typically celebrated by American Jews generally and by his own family in particular.

Cox's chapters often begin with an initial Christian response to the holiday. Describing the "near-euphoric" singing and dancing of Jews during Simhat Torah-the celebration that marks the end of the annual reading of the five books of Moses-Cox explains, "it is the holiday when Jews act most like Pentecostals." But the dancers "are hugging large, rolled-up scrolls encased in silk covers": Torahs. He quickly turns from first impressions to deeper lessons: "It is a holiday in which I catch a glimpse of something utterly fundamental to Judaism . . . that for Jews the Law is not a burden, a hindrance, or an obstacle to living a fully human and vitally spiritual life. . . . It is a generous gift which God bestows on his people simply out of love." In the process of learning about Judaism, Cox often reports being disabused of his previous stereotypes about Judaism as an onerously "legalistic" faith with a God whose concern is more with punishment than love of His people.

But Common Prayers is more than a corrective to Gentile misconceptions about Judaism; Cox also delves into many of the fundamental dilemmas with which modern Jews wrestle. When he accompanies his wife and son to synagogue on Yom Kippur, the Day of Atonement, he is struck by the section of the service in which the congregation recites, "We have dealt treacherously, we have spoken slander, we have acted perversely . . . we have done violence, we have framed lies . . . scoffed, revolted, rebelled." Of course, Cox realizes, most of the people in the congregation have not committed these sins, but since there are some in the community who have, everyone must recite it. This raises an obvious question: Can anyone actually repent for someone else? Cox uses this as a springboard for a lengthy discussion of collective repentance. Drawing on his own Protestant tradition, he asks, "Wasn't Luther right? Doesn't repentance require a change of heart by the transgressor, an intention to try to do better?" While Cox remains unsatisfied with the answers he receives, there are other parts of Yom Kippur that he believes Christians might learn from: for example, the requirement that Jews first seek forgiveness from their fellow men for transgressions against them before they seek forgiveness from God.

Cox's effort to create common ground for Christians and Jews can occasionally descend into silliness. He argues that Sukkot-the Jewish harvest festival-should return to its original prominence in the Jewish calendar (from which it receded as agriculture became a less common occupation) because we are facing an "ecological deadline" of limited natural resources. While it is true that during Sukkot and Ash Wednesday, Judaism and Christianity emphasize the fragility of all life, neither holiday was meant to commemorate, as Cox suggests they should, the twin disasters of global warming and El Nino.

The most interesting parts of Common Prayers describe how, over the years, the Jewish rituals, in which he originally participated for his son's benefit, have become spiritually meaningful for Cox himself. For instance, after initially finding it hard to understand the extensive search for chametz (leavened-bread products), which must be cleaned from the house before Passover begins, Cox ultimately likens the ritual to the Christian process of "searching one's conscience." "While looking for crumbs," he writes, "I am sweeping the junk from my own soul."

Cox's exercise in interfaith dialogue has a pressing purpose, beyond a general desire to promote harmony. "I want to question the idea," he writes, "that a Jewish-Christian marriage necessarily dilutes the substance of either or both spouses' faiths." With intermarriage rates for the Jewish community having long ago topped 50 percent, rabbis of all denominations have recently tried to launch an attack on what they see as a growing threat to the survival of Judaism. A couple of recent major studies have shown that children of intermarried couples are far less likely to go to synagogue, join Jewish organizations, and receive a Jewish education than children of two Jewish parents. Cox offers his own experience to counter these claims. And after reading his account, one has little doubt that Nicholas will have a fairly strong Jewish identity-probably stronger than many of his Hebrew-school classmates.

The problem, of course, is that Cox and his wife are the exception rather than the rule. Not only did they consciously choose to raise their son in the Jewish faith (most intermarried couples choose not to- opting instead for Christianity, for a combination of both faiths, or for neither), but Cox has thrown himself into Jewish practice wholeheartedly. And he has found Judaism itself so fulfilling that he encourages other Gentiles who marry Jews to make sure their children "will not be lost to the Jewish people" but "will be considered Jewish and will be nurtured and educated to grow up with that realization."

Citing the relatively small number of Jews who remain in the world (14 million, compared to 2 billion Christians), Cox proclaims that Catholics and Protestants alike must take "every measure possible to ensure that Jews-as a people-will continue to be numbered among the peoples of this earth." Most Jews, of course, would welcome his telling those Christians who intermarry that, given the fewness of Jews and the importance of what they represent in the world, it would be better to raise their kids Jewish. But Cox's arrangement is extremely atypical, and it's hard to imagine its widespread adoption by interreligious couples.

Reading Cox's startling exhortation to his fellow Gentiles, along with his sympathetic account of the Jewish religion, one cannot help wondering why he doesn't just convert. In a way, it seems, he already has.