Alan Lomax (1915-2002) is arguably the most popular and influential American folk song collector of the 20th century. Pursuing a mission of both preserving and popularizing folk music, Lomax moved between political activism, the scholarly world, and the world of popular culture. Based largely on primary material, the book shows how Lomax's diverse activities made him an authority in the field of folk music and how he used this power to advocate the cultures of perceived marginalized Americans - whom he located primarily in the American South. In this approach, however, folk music became an abstract idea onto which notions oscillating between hope and disillusionment, fear and perspective were projected. The author argues that Lomax's role as a cultural mediator, with a politically motivated approach, helped him to decisively shape the perception and reception of what came to be known as American folk music, from the mid 1930s to the late 1960s.