Hiroko Masuike/The New York Times

If ordinary people were caught doing what Valerie Solanas did, they would probably have their library cards taken away and would be admonished: Don’t even think of asking for another book here at the New York Public Library. Ever.

But Valerie Solanas — a feminist loner mainly remembered for shooting Andy Warhol — was not an ordinary library patron. She marked up a book’s cover and several pages inside. Apparently, no one realized what she was doing and alerted the staff.

Fifteen years or so went by before anyone noticed, and by then, she was dead. And because the book had been hers in the first place — she was listed as the author, after all — her annotations, said Thomas Lannon, the library’s assistant curator of manuscripts, were more like copy-editing by a very angry author.

As it happens, Wednesday is the 25th anniversary of Warhol’s death after gall bladder surgery at what was then known as New York Hospital-Cornell Medical Center, 19 years after Ms. Solanas opened fire and wounded him. She was angry because he had lost the manuscript of a play she had written — a play with an unprintable title that she wanted him to consider.

The library book was the “S.C.U.M. (Society for Cutting Up Men) Manifesto.” The opening sentence called on women to “overthrow the government, eliminate the money system, institute complete automation and destroy the male sex.” It was published in paperback; the library had its copy bound in hardback, to minimize the wear and tear, in mid-1976.

Mr. Lannon speculated that Ms. Solanas slipped into the library in 1977, when she apparently returned to New York for the first time in several years. She had served time in prison for the 1968 shooting of Warhol and had been in and out of mental institutions, including one in Florida.

At the library, she would have filled out a slip requesting the book. It would have been pulled from the shelf and handed to her, he said.

Ms. Solanas scratched out her name on the cover and wrote “by Maurice Girodias.” Mr. Girodias, who had published that version of Ms. Solanas’s text, was famous for having published Vladimir Nabokov’s “Lolita,” which had put him at odds with censors in France. He published Ms. Solanas’s 11,000-word text under the imprint of his Olympia Press.

“She’s creating intellectual capital,” Mr. Lannon said, “but it’s being taken away from her — I think that’s how she saw it.”

In her anger, Ms. Solanas wrote “flea” beside Mr. Girodias’s name inside the book. She also wrote, “Read my version and events in my next book.” (She told The Village Voice she had received a $100 million advance for that next book — from “the mob.”)

On the title page, she wrote “This is not the title.” She also wrote that Mr. Girodias’s edition was “full of sabotaging typos.”

On the copyright page, she wrote “LIES! FRAUD!” She also circled “S.C.U.M.” and wrote, “Never! Never!”

Inside the back cover, she wrote, “Lies! Lies!” Then she signed her name.

Ms. Solanas did some copy-editing on the back cover, too. The published version had white lettering on a red background. “Only three years ago, we used to make fun of Valerie Solanas, agitator, writer and would-be revolutionary — with her wild, insane radical feminism,” it said. “Then we were horrified when she shot Andy Warhol in 1968, just to make a point.” She crossed out the last five words and wrote, “Lie.”

“It’s a question of authorship,” Mr. Lannon said. “She has a problem with the way it’s being presented. They call it a manifesto, but to her it’s just ideas.”

He cited a 1977 interview with The Village Voice in which she said SCUM was not an organization. “I thought of it as a state of mind,” she said. The following week, in another article in The Voice, she said Mr. Girodias’s Olympia Press edition was inaccurate. She said that “words and even extended parts of sentences” had been omitted.

Ms. Solanas died in 1988 at age 52. Mr. Lannon said the library had never looked for the slip she had filled out when she requested the book. “The fact that it’s signed by her is enough,” he said.

The library transferred the little volume to its Manuscripts and Archives Division once it discovered her changes. It reasoned that she had turned it into an artifact. “You go to the Temple of Dendur” at the Metropolitan Museum of Art, Mr. Lannon said, “and you see where 19th-century travelers scratched their initials” on the ancient Egyptian stone.

“That’s one thing,” he said. “This is like an edit.”