Rosa's disillusionment with her parents' values stems from four years in Cuba, which have cured her of revolutionary socialism for life. But what to replace it with? To her militantly secular parents' horror, she chooses Orthodox Judaism, into which she strays by chance when she passes a dowdy synagogue and on impulse goes inside.

The journey towards Orthodoxy by young people runs counter to the path charted by earlier generations of Jewish writers, from Isaac Bashevis Singer and Chaim Potok to Philip Roth, many of whose characters wrestled with the challenge of leaving their parents' stifling world to embrace modern society. The return trip being taken by their children is one that an increasing number of baffled Jewish parents of varying degrees of observance or none are experiencing today and it forms the intellectual heart of this novel.

While Heller tends towards caricature in her portrayal of New York progressives, admittedly with style and wit, her view of the Orthodox world is much more nuanced and sympathetic. Observant Jews get all the best lines, and for once they are not wisecracks. "Well, here we are," a rabbi muses to Rosa when she travels to the ultra-­Orthodox community of Moncey to experience the Orthodox Shabbat, "talking about Hashem, a power and an intelligence that passes all human understanding. Don't you think He deserves at least the same courtesy that you extended to Mr Marx?"

For all her mockery of the wreckage of progressive values, Heller isn't above a bit of political correctness herself: while Rosa embraces Judaism, Karla embraces an Egyptian co-­worker in what looks like a rather clumsy attempt at "balance". But she does skilfully depict Rosa's journey as decidedly erratic, two steps forward, one step back (or vice versa as far as Audrey is concerned). A trip to a mikvah (ritual bath) is in danger of putting her off the whole thing but a one-night stand with an old college acquaintance is no consolation either. For her, the destination remains a land of vague promise, over the horizon, not the certainty she craves