LONDON — Earlier this month, Gibson Square publishers here announced that it would publish “The Jewel of Medina,” a novel about the early life of A’isha, one of the wives of the prophet Muhammad.

Despite fears by some that it would offend and inflame Muslim extremists, Martin Rynja, Gibson Square’s publisher, said that it was “imperative” that the book be published.

“In an open society there has to be open access to literary works, regardless of fear,” he said. “As an independent publishing company, we feel strongly that we should not be afraid of the consequences of debate.”

But in the early hours of Saturday morning, Rynja’s house in North London, which doubles as Gibson Square’s headquarters, was set on fire.

Three men were arrested on suspicion “of the commission, preparation or instigation of acts of terrorism,” the police said.

No one was injured in the incident.

A fourth suspect, a woman, was arrested Sunday on charges of “obstructing police” after the police conducted searches of four houses in and around London.

Rynja “has shown nothing but courage,” Sherry Jones, the author of “The Jewel of Medina,” said Sunday in a telephone interview from Spokane, Wash.

The book tells the story of the relationship between the Prophet Muhammad and A’isha, who as a child married Muhammad and is often described as his favorite wife.

Ballantine Books in the United State had bought the rights, but scrapped plans after being warned that the book “could incite acts of violence by a small, radical segment,” Thomas Perry, deputy publisher of Random House Publishing Group, was quoted as saying by The Wall Street Journal.

The most alarming warnings apparently emanated from Denise Spellberg, an associate professor of history at the University of Texas at Austin.

Sent the book in advance, she determined that it was “an ugly, stupid piece of work” and “soft-core pornography,” she told The Journal.

But in the interview, Jones, 46, disputed Spellberg’s characterization, saying the book is “an epic love story and a story about women’s empowerment” and is neither overtly sexual nor offensive.

After Ballantine canceled the book, it was picked up by Beaufort Books, a small New York company.

On Sunday, its president, Eric M. Kampmann, said that “The Jewel of Medina” had already been shipped to bookstores and that publication would go ahead as scheduled.