"What do you think makes the witchcraft trials so fascinating to us as adolescents?” asks Stacy Schiff, who has an engaging habit of inviting her interlocutor to ponder questions with her. “Was it because [the accusers] were empowered girls? That they had secret powers in the way we all want to when we’re kids?” With The Witches: Salem, 1692, due from Little, Brown in October, Schiff, now 53, has finally vented her own teenage fascination with the panic that swept through several dozen colonial Massachusetts villages in the late 17th century.

Schiff’s atmospheric account recreates the religious, social, and political context in which a vast satanic conspiracy against the Massachusetts Bay Colony seemed plausible to otherwise rational people. Authorities there executed 19 alleged witches and wizards, including some of the community’s most respectable citizens and a minister, after accusations were leveled by several “afflicted” young women, who are now generally considered to have suffered from conversion disorder (aka clinical hysteria). While Schiff doesn’t scant the spectacular behavior of the afflicted—who twitched, shrieked, and went into convulsions as they claimed to be tormented by specters visible only to them—she reminds us that the courtroom was firmly controlled by male judges, and that adults of both genders often directed or deflected the accusations.

“Clearly there’s some jockeying for position and grudge-settling that’s being done through the girls—antipathies that we sense but can’t know because they’re not really documented,” Schiff says. “I’ve often thought that international relations are easier to fathom than local gossip!”

Schiff, who has two daughters and a son, explains that every one of her books came out of some sort of obsession: “I am from a small, insular New England town, which I tried to escape for the first 16 years of my life, and I have an adolescent girl at home. I’m sure in retrospect those things influenced my choice of subject. But it was largely that I felt I hadn’t cracked the riddle about women and power with Cleopatra [published by Little, Brown in 2010]. The other moments in history in which women play a role are few, and Salem was one where their role is sensationally important, but we have a completely skewed idea of what happened.”

The Witches, Schiff says, is similar to her bestselling biography of the ancient Egyptian queen in that “it’s something we all know about, but we actually are relatively misinformed.” She adds: “There was a certain crazy parallel in my mind between the two books. Is it logical? Not at all. A person who writes about Cleopatra should go on to write about Caesar; Saint-Exupéry’s biographer should go on to La Rochefoucauld.”

Instead, Schiff moved from her 1994 portrait of the French aviator and writer, her debut book, to the unusual—and Pulitzer Prize–winning—Vera (Mrs. Vladimir Nabokov): Portrait of a Marriage (Random House, 1999). “I wanted to do a [book about a] family relationship,” she says. “I’d already [written about] one person’s life, and I thought this would be more interesting. I wanted to do something more complicated and ambitious.”

In quicksilver conversation in her midtown Manhattan office, Schiff, dressed in jeans and a white cotton top, displays the same sharp intelligence and eclectic interests that distinguish her body of work. “I just don’t like to write the same book twice,” she says. “There’s a great line in Orwell: ‘By the time you have perfected any style of writing, you have always outgrown it.’ I feel that way about a book; by the time you’ve perfected how to approach a subject, you’re done with it—or at least done with that kind of book.”

Schiff once again took a new approach in A Great Improvisation: Franklin, France, and the Birth of America (Holt), her 2005 nonfiction account of Benjamin Franklin’s diplomatic mission to France to solicit support for the American Revolution. “I thought, let’s take somebody we know so intimately and look at an underexamined part of his life,” she says. “Franklin was out of context, which is always a great way to see someone in the round. Also, the documentation had really not been used, because it was sitting in the French state department’s Quai d’Orsay archives: hands down, the worst place to work in the world. You have to fill out a form to use the bathroom! Then I realized he was at Versailles with all these other ambassadors who were writing back to their home courts, so I spent six months finding the Viennese, Portuguese, and Corsican records—great original material, but incredibly difficult to track down.”

As Schiff’s zestful catalogue of her archival trials attests, her books are based on serious scholarly research, yet they’re conveyed in bright, accessible prose. “You just set out to write the most irresistible book you can,” she says. “I think shaping is imperative, and you don’t really know if you’ve succeeded until five years later. With Witches, there was a sense that I had always gone horizontally and I wanted to go vertically. The Witches has a huge cast of characters, but it takes place over only nine months. It’s a completely different way to structure and write a book, and it took me the longest time to figure out.”

The problem, Schiff says, is that there have been very few narrative accounts of what happened in Salem. “Most of the really good books are thesis driven: it was geographic hostility, or it was the trauma of Indian warfare, or it was conversion disorder. I felt that was cheating. The whole point is that you want readers to want to turn the page—you don’t want to tell them, here’s what you should be thinking. It took me a while to realize that you have to in an almost guileful way restrain yourself and keep things from the reader, or at least downplay them as you’re narratively moving through. It was difficult, in that I was doling out information a little more sparsely, because I wanted the reader to pick up the hints and put them together. Only at the end do I say, oh, yes—if you saw this and this and this, that’s how the pieces fit together. I thought back-loading the explanations was essential to make [the book] more readable.”

Michael Pietsch helped her rein in the colorful-but-excessive social history background, Schiff says, but she adds: “I never work closely with an editor until I finish; I tend to do the territory-reconnoitering piece myself. You can only go where the material takes you; no one else can solve it for you.”

It was the pleasures of “that deep dive into the material” that lured Schiff from her satisfying job as a senior editor at Simon & Schuster. “I thought I would go back, because I really loved publishing,” she says. “But there’s something thrilling about being able to inhabit another place, a foreign country as it were: that sense that you’re leading a dual life, living in two worlds and taking that other world with you wherever you go.”

Wendy Smith is a contributing editor at The American Scholar and reviews books for the Washington Post, the Boston Globe, the Los Angeles Times, and the Daily Beast.

Correction: In the print version of this article, we ran the incorrect photo, which is of Amy Stewart. The above photo is the correct photo of Stacy Schiff. We apologize.