Appalachian music is often imagined as a homegrown mountain tradition, but this episode makes the case that it was the original global mixtape: unaccompanied ballads like "Barbara Allen" and "Matty Groves" from northern England, Scotland, and Ulster; Neil Gow's short "saw stroke" fiddle bowing; German-derived dulcimers and the half-yodel known as vocal feathering; and the gourd banjo, clawhammer technique, washboard, and gutbucket bass of Affrilachian communities, with the blues supplying the harmonic structure that later defined bluegrass and country.

The conversation follows the shift from Old World ballads to broadside songs about train wrecks and murders, the "high lonesome sound" and gapped pentatonic scales, coal-mining protest songs like "Which Side Are You On?" and "Sixteen Tons," and the lined-out hymn singing preserved in Old Regu ...