William J. Mann (born August 7, 1963) is an American novelist, biographer, and Hollywood historian[1] best known for his studies of Hollywood and the American film industry, especially his 2006 biography of Katharine Hepburn, Kate: The Woman Who Was Hepburn. Kate was named one of the 100 Notable Books of 2006 by The New York Times.[2] William J.Mann also used the pseudonym Geoffrey Huntington[3][4] under which he wrote the Ravenscliff Series.[5]