Michael Zelig Castleman (born February 2, 1950) is an American journalist and novelist, based in San Francisco. During a 35-year-career, he has published 13 nonfiction books and more than 2,500 magazine and Web articles. His nonfiction titles have more than 2.5 million copies in print. As a novelist, he has written four murder mysteries set in San Francisco that deal, in part, with the city’s rich history.