 These works dwell on the duality of the soul; the nature of good and evil; issues of redemption, salvation and damnation amongst others.The Scottish concept of the "Caledonian antisyzygy", the duality of a single entity, is a key driving force in Scottish literature, and it appears especially prominently in the tartan noir genre.Modern crime writers have also been influenced by 1930s and 1940s United States masters of the hard-boiled genre, particularly Dashiell Hammett and Raymond Chandler.