Cujo is a horror novel by Stephen King, publishe by Viking in 1981. The book tells the story of the middle-class Trenton family and rural Camber clan in Castle Rock, Maine. Mundane marital and financial difficulties plague disgraced advertising man Vic Trenton and his adulterous wife Donna. Their domestic problems are dwarfed by mortal danger when Donna and her four-year-old son Tad are terrorized by a rabid St. Bernard named Cujo. The novel was adapted into a 1983 film of the same name.