PARIS - US author William H. Gass, who worked on his mega-novel “The Tunnel” for three decades, has died at the age of 93, his French publisher said Thursday. The author, known for a bleak style which earned him comparisons to William Faulkner, died Wednesday, publisher Cherche-Midi said, without saying where. Clocking in at some 650 pages, “The Tunnel” - published in 1995 after some 30 years of work - won the American Book Award for its dark depiction of a historian specialising in Nazi Germany.