Schiff’s new nonfiction book, The Witches: Salem, 1692 (Little, Brown), revisits the 17th-century trials that traumatized colonial Massachusetts, which she says have been “our national nightmare” ever since.

How was writing this book different from, for example, Cleopatra or Véra (Mrs. Vladimir Nabokov)?

The Witches posed narrative challenges no other book has. People swear to things that could not have been true but that they heartily, deeply believe to be true, which leaves one to attempt to write a precise, meticulous book of nonfiction with an illusion at its core. It’s like photographing ghosts.

Is that why you open with an account of flying on a broomstick and crashing from the point of view of a woman who testified that she had actually done this?

I felt I had to begin with someone who very sincerely and obediently delivered this story that to us would seem half-baked, because these poor, befuddled accused women were being interrogated under intense pressure and asked leading questions by the judges. They came to believe the stories themselves. And, of course, if you agreed with the authorities and confessed, you saved your life. Besides, how could I pass up a broom crash?

Did you want to prevent readers from feeling smug about the mistakes made in Salem?

I wanted to make sure they understand that these were not benighted, medieval people; they were very literate and educated. I think we, too, have had that sense of things falling from the air and invading our space and making us feel vulnerable in a way that we hadn’t felt before, so that civil liberties were expendable for the sake of national security. It would be good not to forget that we are just as capable of that kind of behavior as they were, and with possibly greater consequences—though not as fantastical. What happened afterward in Salem is really interesting to me because, how do you go back to living alongside people you’ve accused—or the families of people you’ve hanged? How society puts itself back together again is really astonishing.

Some of the accusers and judges regretted their actions afterward, didn’t they?

I give high marks to Samuel Sewall, one of the judges, who publicly apologized in his church five years later. But there are a number of other people who could have apologized and, as far as we know, never did. William Stoughton, the chief justice, would obviously be at the top of the list. Again, we’ve done the same sort of thing ourselves: sweeping something under the carpet is always ever so much more preferable to saying, for example, that invading Iraq was a mistake.