Few cinephiles would deny the importance of mood in film, yet the aesthetics of mood are curiously overlooked today. On the one hand, mood is an essential dimension of cinema: we define certain genres, for example, by suggesting the moods they evoke (suspense, the thriller, the romance). On the other hand, words frequently fail us when we try to articulate such moods in a more abstract or analytical vein. I offer in this essay some critical reflections on the significance of mood, suggesting that mood works in narrative film by the disclosure of cinematic worlds. To explore variations in the aesthetics of mood — what I call disclosive, episodic, transitional and autonomous moods — I shall consider some selected mood-sequences from Brokeback Mountain (Ang Lee, 2005), Fa yeung nin wa/In the Mood for Love (Wong Kar-wai, 2000), Habla con ella/Talk to Her (Pedro Almodóvar, 2002) and Mulholland Drive (David Lynch, 2001). My aim is to suggest the virtues of taking a more phenomenological approach to the aesthetics of mood, understood as a way of revealing or opening up a cinematic world; and to show how mood, in revealing distinctive cinematic worlds, is essential to our aesthetic and emotional engagement with film.