The History of Horn Playing in Los Angeles from 1920 to 1970 begins with the horn players who played in the silent film orchestras and the Alfred Brain's tenure with the Los Angeles Philharmonc. This study details the introduction of sound tracks, the early studio orchestras, the contact studio orchestras, the musician union's role in structuring the work environment, the horn players who played in both the Los Angeles Philharmonicand the studios, major figures from the subsequent freelance perios such as Vincent de Rosa, and the local and international influence of the Los Angeles Horn Club.