For a long time, the term "folk music" meant music made by ordinary people rather than by professional musicians. In many cultures around the world, and over many generations, songs were handed down from one person to the next. Good folk songs survived over time because they spoke to basic human emotions and told stories that everyone could relate to. In the twentieth century, with the rise of commercial popular music, folk music was no longer just music made by ordinary folks; it became a style of music that had commercial appeal as well.

During the twentieth century in the United States, folk music went through a number of transformations. In the 1930s, during the Great Depression (see entry under 1930s—The Way We Lived in volume 2), folk singers sang songs about the hard times people were going through. One of the most important artists was...