Hallie Ephron has lost count of the number of times well-intentioned people have told her a story they thought she could use as writing fodder. But the bestselling author arrives at BookExpo this year to promote her fifth suspense novel, You’ll Never Know, Dear (Morrow, June), which was not only informed by the real-life experience of a friend but uses it as its backbone.

“Her mother was a doll collector,” says Ephron of this friend. “She had to move out of her big house in the South, and every time my friend looked under the bed, she’d pull out a box of doll parts. A million people have said to me, ‘[My story] would make a great book!’ This was the first time it was true.”

Dolls permeate the story, providing a critical element of eeriness—much in the same way, says Ephron, that clowns often infuse us with dread. “I remember leaving my doll in my bedroom and sneaking back up to see if she was in the same place when I burst through the door,” Ephron says. “If she was human, would that be a good or a bad thing?” In You’ll Never Know, Dear, a doll maker fashions lifelike porcelain “portraits” of two young sisters, one of whom disappears along with her miniature doppelgänger. Forty years later, the doll reappears, reopening family wounds and adding a new and urgent twist to a never-solved mystery.

Ephron says such mystery is essential to her novels, which are pegged in the market as suspense—although she prefers the British term crime fiction. “That’s the best umbrella, I think, encompassing thrillers, suspense, mystery,” she says. “What’s important to me is that the book is driven by the reader’s feeling of anticipation about what’s going to happen next—a feeling of tension, not of things exploding. I’m reaching for the chill that runs down people’s backs.” To achieve that, in You’ll Never Know, Dear, she wrote the stuff of her own most primal fear: that something bad could befall her children when they were young. Equally essential to Ephron’s work is the framework of family.

This book, like her other fiction (she’s also written four works of nonfiction), features multiple generations of women. It’s a comfort zone, perhaps, for a writer who hails from a family of four sisters (including authors Nora, Delia, and Amy), headed by a strong matriarch (screenwriter Phoebe). It also forms an essential element of structure, which Ephron calls a “comforting thing. Starting out,” she says, “I knew there would be sisters.”

Today, 10:30–11 a.m. Hallie Ephron is signing in the Autographing Area, at Table 5.