Revelations by the novelist Alice Munro’s youngest daughter that she had been sexually abused by her stepfather as a child, and that Munro stayed with the abuser even after he was convicted of the assault, reverberated in Canada and across the literary world on Monday.

The story, told by Munro’s daughter Andrea Skinner in an essay in The Toronto Star and reported by the same newspaper, left many of Munro’s admirers reeling, wondering how a writer of her stature was able to keep such a secret for decades and how the revelations might impact her towering legacy.

“Alice was always kind of Saint Alice,” said Martin Levin, the former editor of the books section at The Globe and Mail. He heard “not even the faintest whisper or hint” of the news in his 20 years at the paper, he said.

For decades, Munro has been revered for her sharply observed short fiction and her insights into human nature and relationships. Even as she won the Nobel Prize in 2013, Munro remained private and unassuming, and described her life in a small town in Ontario as ordinary, quiet and happy.

That image of Munro, who died in May at age 92, shattered on Sunday.

The Canadian novelist Margaret Atwood wrote in an email that she was “blindsided” by the revelations. While she had learned a bit about the cause of the family rift a couple of years ago, from one of Munro’s other daughters, she never knew the full story until she read Skinner’s account.

“Why did she stay? Search me,” wrote Atwood of Munro’s decision. “I think they were from a generation and place that shoveled things under the carpet.”

She added, “You realize you didn’t know who you thought you knew.”

On social media, a cascade of writers and journalists, including Lydia Kiesling, Brandon Taylor and Jiayang Fan, expressed shock and heartbreak at the news. Others, including the novelist Rebecca Makkai, wondered whether from now on it would be possible to divorce Munro’s transcendent writing, which occasionally explored tumultuous domestic circumstances and sudden estrangements, from her troubling behavior.

“These revelations not only crush Munro’s legacy as a person, but they make the stories that were, in retrospect, so clearly about those unfathomable betrayals basically unreadable as anything but half-realized confessions,” Makkai said in an email. “To me, that makes them unreadable at all.”

Skinner wrote that the abuse began when she was 9 years old and went to visit her mother and stepfather. Fremlin climbed into bed with her, Skinner wrote, and sexually assaulted her. She told her stepmother, Carole Sabiston, who told Skinner’s father, Jim Munro. He decided not to tell his ex-wife, Alice. Skinner wrote in The Star that Fremlin continued to expose himself to her for years.

When Skinner was in her 20s, she told her mother in a letter what Fremlin had done. Skinner wrote that Munro reacted “as if she had learned of an infidelity.”

Fremlin wrote letters to Skinner’s family, describing the abuse but blaming her. Years later, Skinner wrote, she took the letters to the police. Fremlin was charged with sexual assault in 2004 and was later convicted of that offense, according to the Ontario Provincial Police.

Munro remained with him. She and Skinner became estranged, and never reconciled.

News of the guilty plea didn’t appear to travel far beyond the small courthouse in Goderich, Ontario, where the case was heard. It didn’t even reach Wingham, the village in Ontario where Munro was born, said Verna Steffler, 84, a longtime friend of Munro’s.

But after Fremlin’s death in 2013, Munro did change her plans to be buried near him in the nearby township of Blyth. Steffler said that when she heard of the change, she thought, “Well, she doesn’t want to be anywhere near him.”

In her essay, Skinner indicated that people beyond the tight family circle were aware of the abuse. “Many influential people came to know something of my story yet continued to support, and add to, a narrative they knew was false,” Skinner wrote.

But it is unclear how widely known Skinner’s story was in Canadian literary and media circles. Skinner did not respond to emails from The Times on Sunday or Monday. Penguin Random House, Munro’s publisher in the United States, declined to comment.

Douglas Gibson, Munro’s longtime editor and publisher at Penguin Random House Canada, now retired, said in an email to The Times that he knew of Munro’s estrangement from her daughter, and learned of the reason for the rift in 2005. “It became clear what the issue was, with Gerry Fremlin’s full shameful role revealed,” Gibson wrote, “but I have nothing to add to this tragic family story.”

Robert Thacker, a literary scholar who published an acclaimed biography of the novelist called “Alice Munro: Writing Her Lives,” said that right as the book wwas going to press in 2005, he got an email from Skinner, describing the sexual abuse she had suffered.

“I think she wanted me to include it,” he said. But the book was done, he said, and he concluded that it wasn’t his place as a literary biographer to delve into fraught family history.

Around 2008, Thacker sat down with Munro again to interview her for an updated version of the biography. She asked him to turn off his tape recorder so that she could discuss Skinner’s story, he said. “This was one of the saddest things in her life,” Thacker said.

The updated biography, published in 2011, omitted what Thacker knew about the abuse.

“I viewed it as a private family matter,” he said.

Thacker declined to share further details about what Munro said regarding the abuse and its impact on the family. Still, he was not surprised that Skinner decided to go public after her mother’s death.

“I knew this was going to happen someday, it was all really a question of when,” he said.

For years, Skinner was estranged from her mother and her siblings. She and her siblings have since reconciled and they have expressed support for her sharing her story about the abuse and the silence around it.

Sheila Munro, Skinner’s sister and the author of the 2002 book “Lives of Mothers & Daughters: Growing Up With Alice Munro,” told The Star that while the family felt it was important to share Skinner’s story, she doesn’t believe the revelations should detract from their mother’s literary legacy.

“I still feel she’s such a great writer — she deserved the Nobel,” Sheila Munro told The Star. “She devoted her life to it, and she manifested this amazing talent and imagination.”

Jessica Johnson, a journalist in Canada who has covered the literary world and a journalism instructor at the University of Toronto, said some celebrities — including literary celebrities — are seen as pristine. “We live in a world of celebrity that tends to see figures like Munro as unimpeachable,” she said.

“But the real Alice Munro,” Johnson continued, “I don’t think any of us knew her.”