"The thing that’s interesting about right now is imagining what I will ever write next,” Dani Shapiro says. We’re sitting at a table in the back of the Smile, a subterranean café on Bond Street in New York City. It’s brisk outside, but the café is cozy and slightly out of time—all wood and candlelight, the tables largely empty except for, here and there, a stylish person sipping from a mug the size of a decorative gourd. The clientele is, I think, largely actors or stagehands, grabbing a quick bite before evening call times at either the nearby Public Theater or the off-off-Broadway theater a few doors down.

No one seems disturbed by the two of us, the recorder conspicuously on the table, my beat-up ARC stuffed with Post-it notes. Shapiro could be an actor, too, lively and radiating warmth, dressed in a long-sleeved black shirt, jeans, and heels, as well as a vest that, at first glance, appeared to be moving. It took me a moment, in the dim lighting, to identify the gently wavering material as dozens of tiny, iridescent black feathers. “It truly does feel to me that everything has led up to this,” Shapiro says.

“This” is Inheritance (Knopf, Jan. 2019), Shapiro’s 10th book and fifth memoir, which tells the story of her discovery at age 54, thanks to an at-home DNA testing kit taken cavalierly one evening, that her father, who died in 1986, was not her biological parent. In elegant prose written with the breathless momentum of a thriller—Jennifer Egan calls Inheritance a “genetic detective story”—Shapiro chronicles the detonation of this news and the life-altering revelations that unspooled in its wake. She soon learns she was donor conceived, the result of a procedure at the Farris Institute for Parenthood at the University of Pennsylvania, a somewhat unconventional clinic led by a maverick fertility doctor.

“Everything that I knew myself to be was that I’d come from my parents, from our ancestors,” Shapiro says. “First there was the shock and disbelief that goes along with a traumatic discovery, but this was, in fact, my story—the story that had always been behind the other stories.” She started writing in some narrative form almost immediately—within a few weeks of finding out, she says—breaking every rule she ever had about how close you can be to an experience while writing about it.

Though Inheritance is a read-in-one-sitting kind of memoir, it’s also a deeply philosophical one—the fireworky story underlaid by Shapiro’s searching investigation, often illuminated by her Orthodox Jewish upbringing, into the question of what makes a person a person. “What combination of memory, history, imagination, experience, subjectivity, genetic substance, and that ineffable thing called the soul makes us who we are?” she asks early in the book. Inheritance can be read as many things—a case study of the ethical fallout of DNA analysis, a surprisingly comprehensive look at the book tours and correspondence that make up a professional author’s life, a master class in transforming critical emails into suspenseful plot points—but that question is its beating heart. “I’m not interested in making a confection,” Shapiro notes; it was clear within minutes of meeting her that she is a person who is constantly on the lookout for meaning.

Shapiro was born in New York City and raised in suburban New Jersey. Her stockbroker father was an Orthodox Jew; her mother was Jewish but “not religious,” though she became observant when the two married. Throughout her life, blonde-haired, blue-eyed Shapiro has been told that she doesn’t look Jewish (as a toddler, she was a poster child for Christmas, featured in a Kodak billboard that hung in Grand Central Station), much to her annoyance—and sometimes anger.

In a moving chapter near the middle of Inheritance, Shapiro describes the ache of longing she felt as a child, as though she was “trapped on the other side of an invisible wall: separate, alone, cut-off, and—worst of all—not knowing why.” This ache drove her to snoop through her mother’s things every chance she got and sent her roaming the neighborhood, trying to insert herself into other families. Later, reading interviews with other donor-conceived people who were never told where they came from, she stumbled across similar descriptions of this ache. “When there is this kind of withheld story,” Shapiro says, “the person from whom it’s being withheld—the child—grows up in the shadow of that story without knowing it, and is formed by it without knowing what she’s being formed by.”

Inheritance picks up on many of the same themes Shapiro has been mining over the course of her prolific career. “My novels, and actually even my very early work, in high school and college and graduate school—they all centered around a secret,” she says. “The power of secrets, what they do to us.” Her novel Family History hinges on a lie, and the others all involve the pull of family, with echoes of this theme of information betrayed or withheld. Her memoirs Slow Motion and Devotion prominently feature her parents. Only her most recent one, Hourglass, about her marriage to screenwriter Michael Maren, has little to do with them.

“The image I keep having is of this vast sort of field, where all my life as a writer I’ve been out there with a shovel like, ‘Okay, that spot seems really fertile. I’m going to dig there for a while.’ ” she says. “And there’s just this pile of dirt and this hole, and that’s a book. And then I do it again. And then suddenly it’s like—there’s that passage in the book where I talk about how I am the black box. It feels like I actually did it. I found the black box.”

We decide to split another glass of wine, but the waitress brings us two entirely full glasses. Shapiro has plans to attend a gala for her friend’s theater company; I worry that she will be late, but she doesn’t seem to mind. “I mean, we don’t choose what obsesses us,” Shapiro continues. “Right? It’s what obsesses us that then becomes our themes.”

There’s something about Shapiro’s manner—that warmth, her openness and curiosity—that makes one want to confide in her. I had suspected this, having heard about her popular workshop retreats, held at hotels and yoga centers in places such as Connecticut and Italy, and her gurulike status among a certain set of aspiring female memoirists. But it surprises me how easily, over the course of our nearly two hours together, I share some of my own family secrets. I tell her that I imagine it will happen a lot—people unloading their stories of missing or mistaken origins—when she hits the road to talk about Inheritance. “It happens to be my story, but I recognize that it’s really extraordinary,” she says. “As a writer, I felt an incredible desire and pressure to do it justice.”

We turn to the topic of nature vs. nurture, and the unique moment we’re living in—when, thanks to the combination of the internet and $59 DNA kits, people can find out life-exploding biological information with unprecedented ease. “There have always been people who were wrong about their paternity, since the beginning of time—fathers whose children weren’t their biological children, who didn’t know,” Shapiro says. “We’re in a very unusual sliver of time. I think in 20 years, the idea that anyone ever kept these kinds of secrets from each other—it’s going to be like cigarette smoking, like, How could anyone have ever done that?”

The fact that I have to lean across the table to hear Shapiro makes me realize, all of a sudden, that the Smile is nearly full. After our conversation, everyone looks a little different—what stories, known and unknown, might each of them contain? “This has been such a journey for me, in moving from these wild swings of thinking it’s all nature, it’s all nurture,” she says. “I think many of us would like to just land solidly at one of those poles and be done with it. But it’s so much more complicated than that.”

Julie Buntin is the director of writing programs at Catapult and the author of Marlena.