'I'm in a one-day-at-a-time mode for most things right now."

Ayana Mathis might well be. Recently the Philly-born, Brooklyn-based Mathis, 39, learned that The Twelve Tribes of Hattie (Alfred A. Knopf, $24.95), her first novel, the first piece of substantial fiction she'd ever published, had been chosen by Oprah Winfrey, goddess of all media, for Oprah's Book Club 2.0.

Mathis will read at the Free Library of Philadelphia at 7:30 p.m. Jan. 24. It's free.

On vacation in Paris, "I picked up the phone," says Mathis, "and there she was at the other end of the line. And the woman had really read my book - she was quoting passages, asking about scenes and characters. She knew it."

From there, stuff broke crazy. Her publisher, Knopf, shoved up the release date and upped the first printing from 50,000 to a whopping 125,000. Last week Mathis recorded a talk with Oprah, at the original Harpo studios in Chicago. It will appear on the OWN network, Oprah's baby, on the Super Soul Sunday program Feb. 3.

When Oprah speaks, people read. It's called the "Oprah bump." Her revamped book club now lives on social media - Facebook, Twitter, Storify, and GroupMe. It creates a far-flung reading circle, thousands strong, that can pose questions to Oprah or the chosen writer.

And it still packs a punch. Mathis' novel is the second choice this year for 2.0. The first choice, Wild, by Cheryl Strayed, went from far down the lists to top 10 in sales, from 85,000 sold to 275,000 in little time.

Mathis is living what many a writer has dreamed about. She was a creative writing student at the University of Iowa and had to write something - so she started a fictionalized memoir. "It wouldn't jell," she says. It was kind of a mess."

But the germ of the memoir was "the story of a little girl in a troubled place," Mathis says. Then main character Hattie Shepherd came along. So did a structure: chapters concerning each of Hattie's surviving children. In just two years, Mathis had finished a draft.

Under the mentorship of her adviser, Marilynne Robinson, Mathis graduated in May 2011. That month, she sent agent Ellen Levine her manuscript. A mini-auction ensued, and by July 1, Knopf had bought it.

"Honestly, so much has been going on that one Sunday I just stayed at home watching bad movies and eating pudding pops," Mathis said by phone from New York.

Oprah was attracted by the name Hattie: Her grandmother's name was Hattie Mae Lee. The story, of a black woman's migration from Georgia to Philadelphia in 1923, paralleled that of Oprah's own family, whose members traveled from Mississippi to Chicago during the Great Migration.

Hattie becomes mother to a large, troubled, multigenerational family. The death of her twins, Philadelphia and Jubilee, embitters her for life. And she passes that coldness, that unresponsiveness, down to the next generations, as happens in families. She does what's required, but hardly without complaint:

"Somebody always wants something from me," she said in a near whisper. "They're eating me alive."

Reviews so far have been mostly admiring. Michiko Kakutani of the New York Times says Mathis "has a remarkable ability . . . to inject the most agonizing events with a racking sense of verisimilitude."

So . . . migration to the North, check . . . dysfunctional, matriarchal family, check . . . feckless, irresponsible black males, check. It seems as if books have gone these ways before, as in Faulkner (and Mathis describes herself as a "Faulkner fanatic"), Maya Angelou, Zora Neale Hurston, Alice Walker, or Toni Morrison. All Mathis can say is that "I have thought long and hard about it."

"I wanted readers to see Hattie as a hero," Mathis says, "but also as a very flawed person. Her sister Pearl calls her 'hard to love.' That doesn't mean she's unlovable - it means loving her is hard work." Hattie also strikes at a cliché, that of "the iron-pillar, strong black woman," which Mathis calls "an unreachable and slightly dehumanizing stereotype."

As for the males, Mathis agrees they "have their failings, but some of them, like Hattie's husband, August, stand up at important times." And as for the troubled family, Mathis says, "Well, everybody has complicated families. Family love is seldom uncomplicated. It can be unconditional, but that doesn't mean it solves everything."

Race is involved, "but it's far from the only factor for these people. I mean, yes, I am black and I'm a woman, but most of the time I'm just a person walking around and living my life." Far from being a novel "about race," Hattie depicts people who face their challenges as they can. One character, Wood, is gay and in the closet. The vengeful Bell has anger issues all her own.

Mathis knows about being a little girl in a troubled world. Born at what was then Woman's Hospital, she grew up in Germantown. Her parents split when she was 2, and her mother, often beset by emotional difficulties, moved from Philly to New York, briefly to California, and back to Philly. Mathis' academic path took her to New York University, the New School, and Iowa.

"One thing I can say is that whatever has happened, my mother and I have stayed very, very close," Mathis says. Mathis now has lived in Brooklyn for 15 years, since "before the wave."

When her mother heard the big news about Oprah, "She kept saying, 'It's just so wonderful,' and then she was silent. A long time. Then she just said, 'My little girl,' in a very quiet voice, almost a whisper, and started sobbing."

Writer on the roll of all rolls, Mathis believes good writing bears a responsibility: "It's to bring readers into a direct, rich relationship with the characters and the situations." In that spirit, Hattie comes to a stern but perhaps redemptive conclusion. "Good writing," Mathis hopes, "lifts us up out of the particulars of people and things, and does more, says more to us. It's the opposite of despair. It's closer to what it means to have a soul, what it means to be a human being."