The Black Douglas is a historical fantasy novel by the Scottish author Samuel Rutherford Crockett published in 1899. It features the historical figures William Douglas, 6th Earl of Douglas (the "Black Douglas"), and Gilles de Retz ("Bluebeard"), though in reality they never met. It is set in Scotland and France in the fifteenth century and blends history with supernatural elements. The novel is cited as an influence for J.R.R. Tolkien's The Hobbit and The Lord of the Rings.