Englander is one of a number of outsider insiders. In 1978, Tova Reich's novel "Mara" depicted an Orthodox rabbi who doubles as a shady nursing-home owner, married to an overweight dietitian so obsessed with food that she gorges herself with five-course meals, even on the fast day of Yom Kippur. The Hasidic hero of her 1988 novel, "Master of the Return" (praised by Publishers Weekly for its "devastating accuracy") abandons his semi-paralyzed pregnant wife in her wheelchair in order to spit on immodestly clad female strangers; at home, he helps his 2-year-old son get "high on the One Above" by giving him marijuana. Reich's 1995 novel, "The Jewish War," told of a band of zealots whose leader takes three wives and encourages his followers to kill themselves. Reich herself prefers not to comment on the level of observance she keeps today, while Englander for his part publicly boasts about eating pork.

Ostensibly about ultra-Orthodox Jews, this kind of "insider" fiction actually reveals the authors' estrangement from the traditional Orthodox community, and sometimes from Judaism itself. Unlike Bernard Malamud, Saul Bellow and Philip Roth, assimilated Jews who have written profoundly about the alienation that accompanies that way of life, the outsider insiders write about a community they may never have been part of.

One of the most popular of these is Tova Mirvis. In her first novel, "The Ladies Auxiliary," the Orthodox women of Memphis appear in an unsettlingly harsh light. One of Mirvis's favorite themes is the oddball ba'al teshuvah (literally, "master of repentance"), a deeply observant Jew who did not grow up as one. Such a type can be seen in "The Ladies Auxiliary": Jocelyn, who after years of keeping kosher still regularly indulges in the shrimp salad she hides in her freezer.

In Mirvis's more recent novel, "The Outside World," we meet Shayna, a mother of five girls living in an ultra-Orthodox Brooklyn community. Shayna supposedly chose a more spiritual life as a young adult, yet now she spends most of her time reading bridal magazines. Another character, Bryan, is a 19-year-old who returns home from Israel as a deeply religious radical, renamed Baruch. Yet at his engagement party, he's suddenly starring in a Harlequin romance: out on the porch, Baruch embraces his fiancée and she leans "in close, their bodies gently pressing against each other." It's bad enough that a yeshiva student would embrace a woman not related or married to him, but to do so in public is even worse. Yet Baruch's younger sister isn't surprised: "They who pretended to be so holy in public were just like everyone else in private. It confirmed what she had suspected: that it was all pretense."

It certainly seems that way. Shayna's supposedly observant husband, Herschel, ignores his job as a kosher supervisor for the Orthodox Coalition while collecting a salary, without experiencing a moment's guilt. Meanwhile, Shayna has a television in her bedroom, "its presence an unacceptable connection to the outside world. It had long ago been smuggled into the house in an air-conditioner box to hide it from the neighbors, all of whom had done the same thing." All of whom?

There will always be people who fail to live up to their ideals, and it would be pointless to pretend the strictly observant don't have failings. But before there can be hypocrisy, there must be real idealism; in fiction that lacks idealistic characters, even the hypocrite's place can't be properly understood. Like other outsider insiders, Mirvis homes in on hypocrisy, but in the process she undermines the logic of her plot. The novel's jacket copy announces that "The Outside World" is meant to explain "the retreat into traditionalism that has become a worldwide phenomenon among young people," but the uninformed reader might wonder why any young person would want to be part of such a contemptible community.

On her Web site, Mirvis says she "did very little research" for her books because "I grew up with all these rules and customs and rituals." People who grow up with some traditional customs may imagine themselves experts, but until they've logged real time among the haredi they may know as little as most secular writers. Come to think of it, they may know less, because a secular writer might do more on-the-spot research.