(FORTUNE Magazine) – As CEO and creative director of the J. Walter Thompson USA advertising firm, James Patterson, 41, often treads a thin line between fact and fiction. But in his other career -- as an award-winning mystery author -- he can legitimately concentrate on just the fiction, ma'am. ''Fiction is a great relaxer,'' he says. ''It takes me away from all the hustle of the advertising business.''

If Patterson keeps it up, fiction may carry him far, far away. The copywriter-become-CEO will have his fifth novel published this month: The Midnight Club, a thriller in which a wheelchair-bound New York City detective takes on the sadistic leader of an international crime ring. Sounds improbable, you say? Hollywood doesn't think so. Patterson sold the film rights to David Brown, the mogul who produced Oscar-winning films like The Sting and Jaws. Patterson will see more tinsel in May, when shooting begins on Honeymoon, a movie based on his first screenplay. Patterson gets up every day at 5:30 a.m. to write for two hours at his dining room table in Manhattan. In 1976 he won an Edgar award from the Mystery Writers of America for his first book, The Thomas Berryman Number. Past winners of the Edgar include big guns Ken Follett and Robert Parker. Despite his literary acclaim, Madison Avenue still has Patterson's attention. ''I always thought that if I made a lot of money writing, I'd leave advertising,'' he says. ''But when my second book was successful, I was depressed. I didn't want to retire. A dual career is exciting. The books removed the urge I felt to compete with my advertising colleagues.'' Could there be a roman a clef in the works? Says Patterson: ''People are always looking for a connection between my characters and people I know, but there really isn't one. The business world just isn't worthy of fiction.'' Hmmm. Try telling that to Tom Wolfe.