This dissertation examines the role of Zilphia Horton (1910-1956) in helping to establish the use of music as a powerful tool to unify and train groups involved in social reform at seminars led by Highlander Folk School. In engaging in what has been termed the “mobilization of music,” Mrs. Horton was active in labor disputes, training seminars in the United States and Canada, and the formation of women’s union auxiliaries from 1935 until 1956. The study uses correspondence written by Horton to her husband, Myles Horton; business letters to labor union officials and contributors to songsters; and writings revealing her methodology for compiling songsters, all of which are found in the Tennessee State Library and Archives and the Wisconsin Historical Society archives. The study will demonstrate the way in which Horton used music on picket lines and seminars by drawing on a long-standing tradition of using contrafacta applied to Appalachian music, hymns, spirituals, and other folk musics of the United States. Her use of traditional folk song and dance also created unity in groups that visited Highlander Folk School. Horton established a tradition of folksong as protest music that influenced the methodology of later music directors at Highlander Folk School, particularly the use of music for social reform during the Civil Rights Movement of the late 1950s and early 1960s.