This document discusses genre theory and its application to defining the thriller genre. It explores different models of genre theory, from traditional views that see genres as having fixed conventions to more contemporary views that see genres as dynamic and blurring between other genres. The document uses examples like North by Northwest, The Shining, Alien, and Memento to examine how films may conform to or challenge genre conventions. It also notes some of the key texts and producers that are often associated with the thriller genre.