Ernest Gary Gygax ( ; July 27 , 1938 -- March 4 , 2008 ) was an American writer and game designer best known for co-creating the pioneering role-playing game `` Dungeons & Dragons '' ( `` D&D '' ) with Dave Arneson .
Ernest Gary Gygax ( July 27 , 1938 -- March 4 , 2008 ) ( IPA : [ ˈgaj.gæks ] ) was an American writer and game designer . He was best known for co-creating the early role-playing game `` Dungeons & Dragons '' ( `` D&D '' ) with Dave Arneson in 1974 .