John Stewart is a fiction writer.
John Stewart Williamson ( April 29 , 1908 -- November 10 , 2006 ) , who wrote as Jack Williamson , was an American science fiction writer , often called the `` Dean of Science Fiction '' after the death of Robert Heinlein in 1988 . John Stewart , known as Green Lantern , is a fictional superhero appearing in American comic books published by DC Comics and was the first African-American superhero to appear in DC Comics .