Film music can be music in its own right, but when it is ‘film music’ it is defined by its function within a cinematic field of reference. ‘How does film music work?’ introduces some of the basic ways in which film music can be meaningful, both in terms of its constitution as music and its function as a component of filmic narrative. Film music does more than define emotion in a film, it generates it. Does film music always have a narrative function? Can film music function non-narratively? Film music creates powerful effects, the product of a mix of two art forms: film and music.