One of the founding acts of modern country music, the Carter Family began recording in the late 1920s and developed a national following that lasted throughout the 1930s and into the 1940s. Among the first stars of hillbilly music, as country was labeled during that era, they created popular versions of traditional folk songs, influencing countless future country and folk artists. Their material included classic songs such as "Wabash Cannonball," and the melodies of their songs were borrowed by other composers—among them Woody Guthrie, who used one of their tunes as the musical basis for "This Land Is Your Land." The group was known for their vocal harmonies, in addition to Maybelle Carter's (1909-1978) innovative guitar technique, in which she used her thumb to pluck out a melody on the bass strings while using her fingers to strum a rhythm accompaniment on the...