WILMINGTON - Unlike J.K. Rowling, she's not richer than the Queen of England. Unlike Lisa Scottoline, she doesn't own a farm with horses (yet).

But make no mistake - Marisa (pronounced "Mareesa") de los Santos, with her second novel,

Belong to Me

(William Morrow, $24.95), about a young Center City couple who move to the Philadelphia suburbs, is now a bona fide New York Times best-selling author. And that's the hardcover list, thank you.

Here comes the new set of problems.

Has the award-winning poet, a graduate of the tony Sarah Lawrence and University of Houston writing programs, sold out? Is this Ph.D. in literature and creative writing appealing to fans of "highbrow mommy lit," as Publishers Weekly nastily suggested? Is Marisa de los Santos literary, or is she not?

"I have to admit," says the sophisticated 41-year-old novelist, chatting in the dining room of her brick Tudor in Wilmington's suburbanish Wawaset Park neighborhood, "I was pretty grateful that when I debuted at No. 5, Jhumpa debuted at No. 1." De los Santos laughs. "She is definitely literary fiction, no questions asked. I felt like, OK, yes, there's Jonathan Kellerman, but look who's No. 1!"

You can understand why best-sellerdom might cause anxiety in this household. De los Santos' husband, David Teague, 43, is also a serious writer, and both have taught for years in the University of Delaware's Associate in Arts program, though de los Santos now focuses full time on writing.

Since they met - Marisa's sister set them up when David was a University of Virginia graduate student and Marisa was a Sarah Lawrence College student pursuing a master's of fine arts - they've spent stretches of their life attached to writing programs and universities. (They married in 1992 and have two children, Charles, 8, and Annabel, 6.)

In such families, best-sellerdom can sound like going over to the other side.

"Her chances of playing in the NBA," jokes tall, lean David, about to head out for a run, "are probably just about equivalent to her chances of being on the best-seller list. Not because she's not incredibly talented, but because it's just so hard, and it takes some luck."

"None of our friends who write and were in those programs holds it against her," Teague confides, "because they know she did the work. Somebody, somewhere, with all of us paying our dues, needs to make it. Certainly her close friends have been nothing but supportive and enthusiastic."

De los Santos knows it's weird for the hyperliterary daughter of a Filipino surgeon from Cebu City and a nurse from Westminster, Md., - she was born in Baltimore, raised in northern Virginia, and won a prize for her volume of poetry,

From the Bones Out

- to be facing such tasteless questions.

"As a poet for years and years," she says, "I had no expectation of having an audience. There's no conversation about sales figures. You don't have an agent, because 15 percent of nothing is not attractive to any agent."

How did the big time happen? Both Teague and de los Santos worked together on screenplays a few years back, drawing her from poetry toward narrative. Then, she likes to say, she started to "hear a voice" in her head, which turned out to be Cornelia Brown.

De los Santos' first novel,

Love Walked In

(its title comes from a Gershwin lyric), boasted many appealing features, including 31-year-old Cornelia, a grad-school dropout who manages a hip Center City coffee shop, Cafe Dora (read "La Colombe").

Cornelia falls for a handsome customer with Cary Grant looks named Martin Grace. Grace doesn't immediately tell Cornelia about his 11-year-old daughter, Clare, or about Clare's mother, his ex-wife, who is battling mental illness. As the story develops, Martin recedes from view, Cornelia bonds with Clare, a fine man named Teo enters the scene, and, according to Washington Post critic Susan Adams "you want to hunker down on a chilly day in a comfy chair and read straight through 'til dark."

Other reviewers also distinguished

Love Walked In

from chick-lit treacle. Margo Hammond, longtime book editor of the St. Petersburg Times, praised it as "a mature narrative" that "doesn't shy away from the down-to-earth realities of messy divorces, bipolar depression, and the untidy complications of the human soul."

Good luck began to strike. While the novel did not sell out its 45,000-copy hardbound printing, it began to take off as a trade paperback thanks to word-of-mouth and bookseller support. Then Sarah Jessica Parker optioned the film rights (though de los Santos doubts the project is going to happen with Parker).

That meant the book industry was paying attention when de los Santos delivered her second novel,

Belong to Me

, in which a married Cornelia and Teo move to a Philadelphia suburb. There Cornelia meets classic suburbanite Piper Truitt, with her "bobbed butter-blond flawlessness," as well as a beguiling single mother named Lake and Lake's precociously gifted son, Dev.

The last business part of the best-seller puzzle fell into place when Barnes & Noble chose

Belong to Me

in April as its seventh selection in the Barnes & Noble Recommends series. Chosen by B&N booksellers from around the country, it's a book, according to B&N, that the chain "recommends unconditionally, believes is 'unputdownable,' and is especially appropriate for book discussion groups."

It's not Oprah, but it moves books.

De los Santos knows that good things about best-sellerdom outweigh the bad: greater press attention, an NPR taping, the projects people are now offering her. At the same time, she chastises literary media for simplistic pigeonholes in regard to fiction.

"Chick lit," she says, is a term "applied so liberally that it really has no meaning, apart from the fact that it usually refers to a book written by a woman." She doesn't believe

Love Walked In

suffered from the "soullessness" that the term supposedly implies.

Nor does she apologize that her books have a little "hope at the end."

"It's just who I am," de los Santos says, noting that she often draws on her own life, including experiences as an adolescent. Cornelia's relationship with Teo, she explains, in some ways certainly reflects her own happy marriage. When a male journalist once told her that men as good as Teo - so at ease with themselves - didn't exist, she demurred.

"My husband is very at ease with himself," she says. "He's a great guy. . . . And he's not the only man I know like that. I have friends who have really good marriages, in that there's tremendous generosity."

In contrast, while she accepts some overlap with Cornelia, she consider herself "not that nice."

How could she be, with people tossing phrases like "highbrow mommy lit" at her? "It's insulting," she says, "not specifically to me, or to mothers, but to anyone, men or women, who write about parenting. . . . It implies most literature about mothers is stupid. . . . In my experience, the relationship between a parent and a child is as complicated as it gets."

"Sometimes people mistake a happy ending for lack of seriousness," she muses. "I don't think happiness is trivial, and I don't think it's easy."

De los Santos and Teague lived in Center City for almost six years, on the 1300 block of Lombard, before moving to Wilmington a few years back. She says she loved being in "the thick of things," when she and David were regulars at La Colombe. ("Full of these beautiful, articulate people who talk about really important things and have seemingly no job whatsoever.")

"I love neighborhoods," she says. "It's not that other people haven't written about Philadelphia, because lots of people have. But it's not familiar terrain for readers in the way New York City probably is. There's a kind of freshness there for a writer."

Her next novel, featuring all new characters, will touch for the first time on the Philippines, a place she's only coming to know firsthand since her parents moved there following her father's retirement. ("I was much more a suburban American girl than I was a suburban Filipino-American girl.")

Meanwhile, although de los Santos says she and David would once "have done just about anything to live in New York," she's enjoying Wilmington. Recently, in what she viewed as a moment of grace, the whole family watched through a window as a fox visited their lawn.

A sweeter pleasure these days than fighting the madness of Manhattan or terminally crowded Brooklyn.

"I don't have to get away from the madness of Wilmington," de los Santos says with a confident smile.