By Jennifer Weiner

Atria. 417 pp. $26

Afew years back, Jennifer Weiner published a novel called "Good in Bed." Featuring a sympathetic, generously sized female writer named Cannie as its protagonist, the book shot onto the bestseller lists and was followed onto those same lists by Weiner's second novel, "In Her Shoes," which featured a sympathetic, generously sized female attorney named Rose. HBO snapped up "Good in Bed," with "Sex and the City" writer Jenny Bicks attached, and "In Her Shoes" should be on view shortly at a movie theater near you, starring Toni Collette and some extra pounds.

Weiner, it seems, has become the star of her own chick-lit success story. Her gift lies in her ability to create characters who both amuse us and make us care; that gift is very much in evidence on her Web log, where she is the central character. Read a few entries, and you'll discover that, like Cannie and Rose, Weiner is a sympathetic, generously sized female who's a disarming combination of self-deprecation and self-confidence. She's chatty but not vapid, and her observations are clear-eyed but never cruel. Her writing, on her blog and in her books, is immensely readable.

Now comes "Little Earthquakes," Weiner's third novel, which is told from four alternating female points of view. We get Lia, a semi-famous actress whose life unravels after the death of her baby boy; Ayinde, a pregnant African American beauty who is married to a Michael Jordan-like NBA star; Kelly, a pregnant Type A super-achieving blonde driven by the specter of her less-than-perfect childhood; and Becky, a sympathetic, generously sized restaurant owner -- who also happens to be pregnant.

What ties these four women together is motherhood. For Lia, who starts off shadowing Becky in the park, slipping rattles and other baby things into Becky's diaper bag when no one is looking, motherhood is the state of grace she's fallen from. For Ayinde, motherhood becomes the battleground on which she ends up fighting for her marriage. For Kelly, motherhood is the straw that breaks the back of her carefully constructed but ultimately hollow life. And for Becky? Motherhood comes naturally, because Becky is as nurturing and grounded as you'd expect her character to be.

The reader spends much of the book wondering along with Kelly, Ayinde, Becky and Lia: Is Kelly's husband a good guy who's hit a patch of bad luck, or is he a selfish slacker? Is Ayinde's husband a noble family man or a smooth operator? Is Becky's husband the perfect man for her -- or a mama's boy beyond rescue? And what about Lia? Will she recover and return to the hunky man who loves her?

By the time the answers come, however, they don't matter quite as much as they should, or satisfy as much as the answers to similar questions posed in "Good in Bed." Compared with Weiner's first novel, "Little Earthquakes" has a slightly diluted quality; it retains a faint taste of poppy fizz, but there are fewer bubbles. And while Weiner tackles some heavy-duty issues here -- the death of a child, growing up biracial in America -- the novel is ultimately less engrossing than her first two, partly because the characters aren't as richly wrought. One Cannie equals more than the sum of Becky, Ayinde, Lia and Kelly.

It should be noted here that there are superbly written books that cover similar traditionally female territory (girl meets boy, or girl gets job, or girl has baby -- and sometimes all of the above): everything from the novels of Jane Austen to those of Cathleen Schine, for example, or the stories of Laurie Colwin and Lorrie Moore. But then Weiner doesn't seem to aspire to a place in this pantheon. She's writing compelling beach books, the kind that sit on the Chick Lit/Summer Reading shelf alongside Terry McMillan and Alisa Valdes-Rodriguez, the kind that will get optioned and turned into feel-good movies. And Weiner's latest probably will make a pretty good movie, too. In fact, one of the book's greatest weaknesses is that the protagonists -- with the possible exception of Becky, who has more heft both physically and emotionally than her mothers-in-arms -- already read like characters in a Hollywood chick flick.

And yet after I'd finished "Little Earthquakes," I found myself missing the characters. Theirs is a world where young mothers invite strange women in distress into their homes, serve them tea and sympathy and tell them, in essence, "You go, girlfriend." It may not be realistic as literary worlds go, but it is reassuring in its warmth and predictability. And judging by the success of chick lit generally and Weiner's books specifically, a lot of us out there are willing -- even eager -- to suspend our disbelief long enough to enter it.