Interest in folk music grew during the 19th cent., although there were earlier scholars in the field, such as Thomas Percy whose Reliques, a collection of English ballad texts, appeared in 1765. Sir Walter Scott's Minstrelsy of the Scottish Border (3 vol., 1803) is a major source on Scottish ballads. Béla Bartók did outstanding work in notating the folk music of central Europe early in the 20th cent., and before him the Russian nationalist composers made use of their country's folk music. Conversely, folk song often shows the influence of formally composed music; this is particularly true of 17th- and 18th-century European folk song.
The collection and transcription of folk music was greatly facilitated by the invention of the phonograph and tape recorder. Using this equipment, John and Alan Lomax gathered many varieties of American folk songs from various cultural traditions throughout much of the 20th cent. Since the early 1950s folk music has become an especially significant influence and source for much popular vocal and instrumental music. Folksingers such as Woody Guthrie and Pete Seeger performed traditional songs and wrote their own songs in the folk idiom, an approach that was later used and modified by Bob Dylan, Joan Baez, and others.
See J. A. Lomax and A. Lomax, Folk Songs, U.S.A. (1948); C. Haywood, ed., Folk Songs of the World (1966); W. R. Trask, ed., The Unwritten Song (1966); E. Martinengo-Cesaresco, Essays in the Study of Folksongs (1976); S. L. Forucci, A Folk Song History of America (1984); P. V. Bohlman, The Study of Folk Music in the Modern World (1988); B. Filene, Romancing the Folk: Public Memory & American Roots Music (2000).