E.M. Forster was a bright, busy young literary star from 1905 to 1910. He produced four highly acclaimed novels, including the bestselling Howard's End. But at the age of 32, he slowed down. It wasn't until 14 years later that he produced another book, his masterpiece and final novel, A Passage to India. And then, more silence.

Despite publishers' expectations that some of their bestselling writers should produce a book a year, the creative process isn't usually so reliably productive. Books appear in fits, starts and hiccups, and sometimes don't appear at all.

Times of silence: E. M. Forster.

At the beginning of their careers, writers may produce several "practice novels" before they are ready to offer something to a publisher, or a publisher is ready to take them on. Peter Carey has three such novels that he has no intention of ever releasing.

Sometimes things slow down later. The American writer Jenny Offill had a gap of 15 years between her first much praised book Last Things and her latest somewhat autobiographical novel, Dept. of Speculation. In it, her character describes running into an old friend: "I think I must have missed your second book," he says. No, she explains, there isn't one. After an awkward moment, he asks "Did something happen?".