Earliest American scholars were with The American Folklore Society (AFS), which emerged in the late 1800s. Their studies expanded to include Native American music, but still treated folk music as a historical item preserved in isolated societies. In North America, during the 1930s and 1940s, the Library of Congress worked through the offices of traditional music collectors Robert Winslow Gordon, Alan Lomax and others to capture as much North American field material as possible. Lomax was the first prominent scholar to study distinctly American folk music such as that of cowboys and southern blacks. His first major published work was in 1911, Cowboy Songs and Other Frontier Ballads, and was arguably the most prominent US folk music scholar of his time, notably during the beginnings of the folk music revival in the 1930s and early 1940s.