The document discusses the history and conventions of the thriller genre, particularly psychological thrillers. It notes that Alfred Hitchcock pioneered many techniques still used in thrillers today through films in the 1920s-1950s. Psychological thrillers often involve characters with dark pasts or unstable mental states set in urban environments portrayed through techniques like voiceovers, diegetic sounds, and fluctuating non-diegetic music to build tension and suspense. Cinematography techniques like point of view shots and over the shoulder shots aim to increase audience emotional involvement in the character's perspective.