Thanks to some breezy Manhattan satire (publishing, trendiness) and a down-to-earth, wisecracking heroine (she's a ""postfeminist"" with no taste for jargon), this basically lightweight and formulaic novel is a good deal more engaging than its Rona Jaffe-ish outline might lead you to believe. Katherine Walden, long-divorced and in her mid-30s, is a well-paid ghost-writer for two bestselling psychologists whom she calls ""Ego"" and ""Altruist"": one ""authors"" inane self-helpers, the other produces fictionalized case histories--and feels that he's ""grown as a writer."" (""About the way Charlie McCarthy grew as a comedian,"" thinks Katherine.) But, urged on by agent-pal Erica, Katherine's now determined to write a novel all her own. And the other ambivalent major relationship in her life is undergoing a change too: her twice-a-week lover, lawyer Nick, leaves his wife and moves in. So Katherine has to deal with a host of new problems (writer's block, crass editors, Nick's guilt-propelled obsession with his stints as a ""Saturday father""), as her quartet of best friends chimes in with bits of dubious advice. In addition to noisy Erica, there's: trendy, WASP-y housewife Paige, whose hubby makes pasta while their precocious six-year-old does imitations of the Odessa steps scene from Potemkin; bestselling novelist Beth, who's into teenage lovers (and sexual free expression for her own kids); and driven fashion-buyer Cynthia, who's doubly demonstrating her liberation by cheating on her professor-husband. Still, despite these flaky ladies, Katherine does fine for a while: her barely-begun novel is sold (sort of)--as she and Nick seem to be moving toward domesticity. But then there's a volcanic Katherine/Nick quarrel (he walks out); the book-sale collapses; Paige finds out that her husband is unfaithful; most seriously (though least effectively), Cynthia attempts suicide, winding up in a mental hospital. And all this opens Katherine's eyes about her chums (a long-overdue realization): she announces her postfeminist credo--""Somewhere along the way we have to stop blaming parents and society and men and everyone except ourselves""--before repossessing Nick and beginning work on a new novel (the very one we've just read, it seems). True, the Nick/Kate problems with romance are threadbare. More annoyingly, the friends are too cartoony to convince. But the ghost-writing digs are right on-target, the assorted children are hilariously bratty, and Kate is bright and brisk enough to make this tartly entertaining well over half the time.