LONDON  Early 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. It was a bold decision: the book’s United States publisher, Ballantine Books, an imprint of Random House, had canceled its publication in August amid fears that it would offend and inflame Muslim extremists. (It has since been bought by another American publisher, Beaufort Books.)

For his part, 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.”

Early Saturday morning, Mr. 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 arson, in which a small fire bomb was apparently pushed through the house’s mail slot. The police were already on the scene as the result of what they described as “a preplanned intelligence-led operation,” and, helped by firefighters, broke down the door and put out the fire.