(La caverne aux livres by gadl / Alexandre Duret-Lutz; some rights reserved.)

It’s a thin tekhelet line, sometimes, the separation between Jews and non-Jews. Occasionally it runs so faint as to make it imperceptible. Or, when you look closely, it zigzags and whirls in a manner closer to abstract expressionism than to the clarity of a cartoon border. Jacob Howland’s Plato and the Talmud (Cambridge, October) examines this phenomenon close to its textual roots, positing that as different as Socrates and the rishonim needed to be to establish two such divergent civilizations, they had in common a number of narrative and pedagogical strategies, as well as, more generally, “the tension between rational inquiry and faith, between the attempt to extend the frontiers of understanding and the acknowledgment of impenetrable mysteries.”


Naomi and Her Daughters

The boundary separating Christians from Jews, in particular, is porous enough at times to encourage utopian universalism or, alternatively, to creep everybody out. Such crossings originate with shared texts like the biblical book of Ruth, the go-to reading for interfaith wedding ceremonies of all sorts. Thus, even though the story seems to valorize a Moabite willing to embrace Judaism out of loyalty to her mother-in-law, Walter Wangerin Jr., a Lutheran pastor and prolific storyteller, can comfortably novelize it without traducing Christian beliefs in Naomi and Her Daughters (Zondervan, September), which Publisher’s Weekly calls “midrashic.”


In modern Europe, the potential surprises and discomforts that can be generated by Jewish-Christian encounters seem limitless. Take Aaron Lustiger, a French kid of Jewish descent who decided to convert to Roman Catholicism in 1940, at the age of 13, and then rose through the religious ranks until he was named Cardinal Archbishop of Paris. (An impressive achievement, even if he couldn’t achieve quite as highly as the protagonist of Isaac Bashevis Singer’s story “Zeidlus the Pope.”) Cardinal Jean-Marie Lustiger on Christians and Jews (Paulist, September) collects his statements, from lectures and interviews, on the subject of his personal religious journey, as well as his perspectives on Zionism, interfaith initiatives, and the Holocaust he narrowly eluded.

In contrast to Lustiger, who eventually had a rather wide audience to whom he could express his feelings on such issues, Edith Stein was murdered at Auschwitz and didn’t get to weigh in on the question of whether she should or should not be beatified. A shapeshifter during her life—born Jewish in 1891, she was more or less an atheist when she wrote a philosophy dissertation under Edmund Husserl and worked with Martin Heidegger; in the 1920s, she converted to Catholicism and became a nun. Her story, and the debate about her sainthood—which the Anti-Defamation League staunchly opposed—are explored by a number of scholars a 1994 collection, edited by Harry James Cargas and newly available in paperback: The Unnecessary Problem of Edith Stein (University Press of America, September).


The rise of these two people, who had been born Jewish, to crucial administrative and theological positions within the Catholic hierarchy might appear a trifle unusual, but the phenomenon of Jews professing their faith in Christ was, by then, nothing new. In The Emergence of the Hebrew Christian Movement in Nineteenth-Century Britain (Brill, September), Michael R. Darby—who received a PhD in Theology from the University of Wales in 2005 and is not the identically named economist—describes how institutions founded by “Jewish believers in Christ” flourished in England in the same century that produced Fagin, Melmotte, Daniel Deronda, and Disraeli.


The Jews of San Nicandro

Stranger still: Interfaith transformations weren’t always just a matter of Jews embracing Christ out of faith or social savvy. Some European Christians have taken the unusual and somewhat hazardous step of renouncing their faith so as to become Jewish. John Davis, a historian of modern Italy, describes one such group in The Jews of San Nicandro (Yale, October). Beginning when a lapsed Catholic cobbler embraced Judaism in a small Italian town in the 1920s, the tale of these new Jews ends in the present, when a small community of their descendants persists in Israel. If nothing else, their journey suggests that Uganda’s Abuyadaya and the Jews of Iquitos, Peru, aren’t wholly unique.


The Pope's Maestro

Occasionally, Jews and Christians manage to get along just fine, without blurring the boundaries between them very much. Such is the case of the American Jewish conductor Gilbert Levine and Pope John Paul II; Levine recounts their “spiritual friendship” in The Pope’s Maestro (Jossey-Bass, October), which begins with Levine searching Kazimierz, in Krakow, for traces of his family’s history. For his loyalty to the pope, and his efforts on behalf of the church’s causes, Levine earned knighthood from the Vatican’s Order of St. Gregory the Great—but that didn’t require him to renounce Judaism.


Spiritual Envy: An Agnostic's Quest

One can renounce Judaism, of course, without embracing some other organized religion. Bay Area radio host and English professor Michael Krasny, for one, has drifted away from the youthful fervor—in his Cleveland boyhood, he recalls, he “led services and chanted Hebrew prayers like a kid smitten, which I was, with Elvis … I tried to sound like a rock-and-roll cantor”—but he has not substituted some other religious absolutism for his eroded faith in a Jewish God. In Spiritual Envy: An Agnostic’s Quest (New World, October), Krasny explains how he wound up committed to “the doubt and skepticism, the certainty or uncertainty of uncertainty recognized by agnostics.”

I'm God, You're Not: Observations on Organized Religion & Other Disguises of the Ego

Krasny notes that contemporary religious figures understand their faiths as means of “detachment from ego”; Lawrence Kushner offers a perfect example of this position. Organizing a collection of remarks on sundry topics drawn from his decades of rabbinical service, he realized that “many of them share a common theme”: the idea that “the real reason for religion is to keep your ego under control.” He titles the book, accordingly, I’m God, Youre Not: Observations on Organized Religion & Other Disguises of the Ego (Jewish Lights, October). If he’s right, the number of ostensibly religious authors, of all faiths, vying for attention in the literary marketplace—with just as much implicit egotism as their secular and atheist peers—suggests that religion might not be doing its job very effectively.

NOTE: This column originally attributed authorship of the book When Bad Things Happen to Good People to the wrong person. It was written by Harold Kushner.