It used to be that American novelists wrote about society or the so-called Great American Dream. In the late 20th century, though, family became the most popular, overarching focus of this country's fiction. And no one has carried us into the 21st century quite like A. M. Homes.

Book by book, Homes has expanded our notion of the family's boundary altogether. In her 1989 debut, Jack, a teenager struggling to grow up suddenly learns his father is gay. Her 1993 In a Country of Mothers, a therapist begins to think her patient is the daughter she gave up for adoption.

At the time her second novel was published, Homes deflected questions about its autobiographical roots. But as she reveals in The Mistress' Daughter (Viking; $24.95), her jagged, searching new memoir, reporters' hunches were correct. An adopted child, Homes never knew the true nature of her roots until they came back to confront her face to face. She reads at Book Passage on April 16.

Almost 15 years ago, Homes' birth mother tracked her down and made it known, through the lawyer who handled Homes' off-the-books adoption, "that if you wanted to contact her, she'd be willing to hear from you."

As Homes writes, the sting of this passive-aggressive approach soon bled into curiosity. She recalls fantasizing that her mother was a glamour puss diva, a free-spirit. "I pictured Audrey Hepburn," she writes.

Would that it had been true. Homes' birth mother was actually a heavily medicated neurotic with no respect for boundaries and a lifetime of regret. Homes was given up for adoption because she was the offspring of her mother's affair with a married man. Getting these details is not easy. Homes hires a PI, then becomes an amateur private dick herself. She phones up old friends and acquaintances.

Homes' sleuthing gradually takes on an obsessive quality that reinforces how, no matter how much detail she possesses, her place is outside the family circle. She tracks down her father and finds him a big, bluff, blowhard with a weird penchant for meeting his long-lost daughter in hotel rooms as if they were having an affair.

The book's second half confronts how this information changed Homes' sense of her self, a more complicated and fraught story. As a novelist, Homes is a connoisseur of narratives; as an individual she has never felt she possessed one of her own. Readers who demand a kind of stylistic unity will be jarred by The Mistress's Daughter, with its frequent shifts in style and voice, its narrative pivots and redirections. But those who are willing to follow Homes will be amply rewarded. Here is a truthful, agonizing story of one woman's search for a narrative life raft. When it's stolen out from beneath her again--as we know it will be--Homes does what she has been doing all along as a novelist: she builds her own.

A. M. Homes reads from The Mistress's Daughter on Monday, April 16, at Book Passage. 51 Tamal Vista Blvd., Corte Madera. 7pm. Free. 415.927.0960.

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