In American music there has been a history of composers who lacked an appropriate vehicle through which to disseminate their music, and several pioneering music journals were founded to expose the music of these composers to a wider audience. In the early part of the twentieth century, many of these journals championed uniquely American music that appeared to break free from European influence. As the century progressed, new journals that focused on modern music led to the recognition and establishment of the avant garde in academia. The institutionalization of the avant garde resulted in the alienation of another group of American composers who did not write neo-tonal music for mainstream audiences. This group, often referred to as the American experimentalists, formed their own distinct tradition, the lineage of which was largely defined and propagated by two journals, SOURCE: Music of the Avant Garde and Soundings. Throughout the twentieth century, music journals like SOURCE, Soundings, and their predecessors presented musical compositions and writings by contemporary composers who had been overlooked by the musical establishment, thereby creating valuable documentation of new music in the United States. This thesis examines the journals SOURCE: Music of the Avant Garde and Soundings in a historical context of new music journals in American culture of the twentieth century. This thesis also illustrates these two journals' contribution to the repertoire and discourse of the American experimental tradition.