Michael John Harrison (born 26 July 1945), known for publication purposes primarily as M. John Harrison, is an English author and literary critic. His work includes the Viriconium sequence of novels and short stories, (1982), Climbers (1989), and the Kefahuchi Tract trilogy which consists of Light (2002), Nova Swing (2006) and Empty Space (2012). He is widely considered one of the major stylists of modern fantasy and science fiction, and a "genre contrarian". He lives in London.