One day this spring, a psychiatrist named Dorothy Lewis got a call from her friend Betty, who works in New York City. Betty had just seen a Broadway play called “Frozen,” written by the British playwright Bryony Lavery. “She said, ‘Somehow it reminded me of you. You really ought to see it,’ ” Lewis recalled. Lewis asked Betty what the play was about, and Betty said that one of the characters was a psychiatrist who studied serial killers. “And I told her, ‘I need to see that as much as I need to go to the moon.’ ”

Lewis has studied serial killers for the past twenty-five years. With her collaborator, the neurologist Jonathan Pincus, she has published a great many research papers, showing that serial killers tend to suffer from predictable patterns of psychological, physical, and neurological dysfunction: that they were almost all the victims of harrowing physical and sexual abuse as children, and that almost all of them have suffered some kind of brain injury or mental illness. In 1998, she published a memoir of her life and work entitled “Guilty by Reason of Insanity.” She was the last person to visit Ted Bundy before he went to the electric chair. Few people in the world have spent as much time thinking about serial killers as Dorothy Lewis, so when her friend Betty told her that she needed to see “Frozen” it struck her as a busman’s holiday.

But the calls kept coming. “Frozen” was winning raves on Broadway, and it had been nominated for a Tony. Whenever someone who knew Dorothy Lewis saw it, they would tell her that she really ought to see it, too. In June, she got a call from a woman at the theatre where “Frozen” was playing. “She said she’d heard that I work in this field, and that I see murderers, and she was wondering if I would do a talk-back after the show,” Lewis said. “I had done that once before, and it was a delight, so I said sure. And I said, would you please send me the script, because I wanted to read the play.”

The script came, and Lewis sat down to read it. Early in the play, something caught her eye, a phrase: “it was one of those days.” One of the murderers Lewis had written about in her book had used that same expression. But she thought it was just a coincidence. “Then, there’s a scene of a woman on an airplane, typing away to her friend. Her name is Agnetha Gottmundsdottir. I read that she’s writing to her colleague, a neurologist called David Nabkus. And with that I realized that more was going on, and I realized as well why all these people had been telling me to see the play.”

Lewis began underlining line after line. She had worked at New York University School of Medicine. The psychiatrist in “Frozen” worked at New York School of Medicine. Lewis and Pincus did a study of brain injuries among fifteen death-row inmates. Gottmundsdottir and Nabkus did a study of brain injuries among fifteen death-row inmates. Once, while Lewis was examining the serial killer Joseph Franklin, he sniffed her, in a grotesque, sexual way. Gottmundsdottir is sniffed by the play’s serial killer, Ralph. Once, while Lewis was examining Ted Bundy, she kissed him on the cheek. Gottmundsdottir, in some productions of “Frozen,” kisses Ralph. “The whole thing was right there,” Lewis went on. “I was sitting at home reading the play, and I realized that it was I. I felt robbed and violated in some peculiar way. It was as if someone had stolen—I don’t believe in the soul, but, if there was such a thing, it was as if someone had stolen my essence.”

Lewis never did the talk-back. She hired a lawyer. And she came down from New Haven to see “Frozen.” “In my book,” she said, “I talk about where I rush out of the house with my black carry-on, and I have two black pocketbooks, and the play opens with her”—Agnetha—“with one big black bag and a carry-on, rushing out to do a lecture.” Lewis had written about biting her sister on the stomach as a child. Onstage, Agnetha fantasized out loud about attacking a stewardess on an airplane and “biting out her throat.” After the play was over, the cast came onstage and took questions from the audience. “Somebody in the audience said, ‘Where did Bryony Lavery get the idea for the psychiatrist?’ ” Lewis recounted. “And one of the cast members, the male lead, said, ‘Oh, she said that she read it in an English medical magazine.’ ” Lewis is a tiny woman, with enormous, childlike eyes, and they were wide open now with the memory. “I wouldn’t have cared if she did a play about a shrink who’s interested in the frontal lobe and the limbic system. That’s out there to do. I see things week after week on television, on ‘Law & Order’ or ‘C.S.I.,’ and I see that they are using material that Jonathan and I brought to light. And it’s wonderful. That would have been acceptable. But she did more than that. She took things about my own life, and that is the part that made me feel violated.”

At the request of her lawyer, Lewis sat down and made up a chart detailing what she felt were the questionable parts of Lavery’s play. The chart was fifteen pages long. The first part was devoted to thematic similarities between “Frozen” and Lewis’s book “Guilty by Reason of Insanity.” The other, more damning section listed twelve instances of almost verbatim similarities—totalling perhaps six hundred and seventy-five words—between passages from “Frozen” and passages from a 1997 magazine profile of Lewis. The profile was called “Damaged.” It appeared in the February 24, 1997, issue of The New Yorker. It was written by me.

Words belong to the person who wrote them. There are few simpler ethical notions than this one, particularly as society directs more and more energy and resources toward the creation of intellectual property. In the past thirty years, copyright laws have been strengthened. Courts have become more willing to grant intellectual-property protections. Fighting piracy has become an obsession with Hollywood and the recording industry, and, in the worlds of academia and publishing, plagiarism has gone from being bad literary manners to something much closer to a crime. When, two years ago, Doris Kearns Goodwin was found to have lifted passages from several other historians, she was asked to resign from the board of the Pulitzer Prize committee. And why not? If she had robbed a bank, she would have been fired the next day.

I’d worked on “Damaged” through the fall of 1996. I would visit Dorothy Lewis in her office at Bellevue Hospital, and watch the videotapes of her interviews with serial killers. At one point, I met up with her in Missouri. Lewis was testifying at the trial of Joseph Franklin, who claims responsibility for shooting, among others, the civil-rights leader Vernon Jordan and the pornographer Larry Flynt. In the trial, a videotape was shown of an interview that Franklin once gave to a television station. He was asked whether he felt any remorse. I wrote: