The spy film genre, which is often considered a subgenre of thriller and/or action, deals with the subject of fictional espionage, either in a realistic way (such as the adaptations of John le Carré) or as a basis for fantasy (such as James Bond). Many novels in the spy fiction genre have been adapted as films, including works by John Buchan, le Carré, Ian Fleming (Bond) and Len Deighton. It is a significant aspect of British cinema, with leading British directors such as Alfred Hitchcock and Carol Reed making notable contributions and many films set in the British Secret Service.