In my thesis I examined the role of sound effects and sound design in the cinema, looking specifically at the sound design work of Alan Splet who created many memorable and groundbreaking soundtracks between 1970 and his death in 1994. Engaging with contemporary sound theorists Splet’s overall contribution to film sound is explored and his influence assessed. When he died Splet left behind a significant sound effects library Sound Mountain and this archive was utilised in this thesis to explore his working methodologies and creative approaches. This archive is maintained by Splet’s partner, the sound designer Ann Kroeber. Splet’s sound design is also explored in relation to the early critical debates by sound practitioners from the advent of sound cinema in 1927. These early practitioners initially outlined a preference for reverberant sound over dialogue intelligibility and, using examples from Splet’s work, the thesis argues that this would have been a preferable direction for cinematic sound to have developed and that an asynchronous approach to the soundtrack, championed by the early pioneers and utilised so effectively by Splet, offers many creative opportunities for contemporary cinema.