Sergi explores the tension between music and sound in the cinema at the time of the coming of synchronized sound in the late 1920s. Focusing on labour relations and the role that professional organizations played in shaping the relationship between sound and music, Sergi describes the complex relationship between musicians and sound artists in filmmaking. The response to the introduction of recorded sound to movies by one of these organizations, the American Federation of Musicians, serves as an example of the power struggles that changes in labour conditions were generating. Sergi provides a useful tool for understanding and interpreting the complex industrial and labour relationships that exist between sound practitioners and composers.