A Google search of the term "genealogy" yields more than 47 million hits. With the growth of the Internet, it is indisputable that the impulse to trace one's ancestors has become a source of passionate engagement for many. Paralleling that phenomenon is the explosive popularity of the memoir genre. These trends converge with considerable power in A.M. Homes's frank and moving new memoir, THE MISTRESS'S DAUGHTER.

Recognized as a keen-eyed observer of contemporary society in her fiction (THE SAFETY OF OBJECTS, THIS BOOK WILL SAVE YOUR LIFE), Homes shifts her vision inward with equal acuity in this work. During a visit to her adoptive parents in Washington, D.C. at Christmas 1992, she learns --- through the family lawyer who had arranged her private adoption in 1961 --- that her mother, Ellen Ballman, who gave birth to her at the age of 22, wants to make contact. Homes's birth was the culmination of a relationship Ellen had had with a married employer almost 20 years her senior.

At first, Homes's engagement with her mother is unsettling, as Ellen lurks around the fringes of the author's appearance at a Washington bookstore and peppers her with phone calls and letters. Their first real meeting, at New York's Plaza Hotel, is poignant, if awkward. After devouring a lobster dinner, Ellen seeks her daughter's forgiveness for giving her up. Homes readily grants it in that encounter, but tensions between them soon emerge. Ellen persists in reaching out to a child who is unwilling to reciprocate the feelings of a woman she considers strange and difficult.

Concealing the seriousness of her medical condition from her daughter, Ellen dies of kidney failure in 1998, and Homes waits until 2005 to open the four boxes of papers and personal effects she removes from her mother's house after her death. When she does, she discovers a bizarre assortment of materials that reveal a life combining incidents of petty crime with the struggle of a single woman simply to survive after her lover's devastating rejection and the loss of her child.

As needy as Ellen is, Homes paints an even more problematic picture of her father, Norman Hecht. He's a respected businessman and father of four, but, as portrayed by Homes, he's little more than a handsome, self-absorbed lout. Most of their encounters take place in hotel lobbies at his request, as if their own relationship has an illicit aspect to it. Shortly after their first meeting, Norman insists that they undergo DNA testing that reveals the near certainty of his paternity. Later, when Homes almost sheepishly applies for membership in the Daughters of the American Revolution, made possible by the English ancestry she traces to the mid-16th century through her paternal grandmother, Norman does everything possible to deny that he's her father.

Homes's prose is spare and uninflected, occasionally bringing to mind the work of Joan Didion ("To be adopted is to be adapted, to be amputated and sewn back together again. Whether or not you regain full function, there will always be scar tissue."). Repeatedly, she returns to this theme of brokenness or the absence of wholeness that has plagued her as a child of adoption. There is considerable emotion in the story's telling, but for the most part it bubbles below the surface of the narrative. The memoir's seriousness is leavened with occasional humor, most notably in Homes's account of Norman's difficulty finding an acceptable payment method for the DNA test.

Homes devotes her final chapter to a loving tribute to her adoptive mother's mother, a vibrant woman who died "unexpectedly" at the age of 99. She writes movingly of her grandmother's inspiration that resulted in Homes giving birth to a daughter at the age of 41, after two years of considerable effort. Somehow it seems fitting that this unusual family saga will continue at least into one more generation.

What gives this memoir its originality and emotional force is that it turns on its head the conventional account of an adopted child on a quest to find her birth parents and instead offers the story of an adult involuntarily introduced to them when they re-enter her life. Despite her initial lack of inclination to discover her roots, Homes finds the journey she's launched on by her birth parents' unexpected appearance a transformative and ultimately rewarding one. In the end, she offers a fitting benediction to this flawed and all-too-human pair: "Did I choose to be found? No. Do I regret it? No. I couldn't not know."