It is rare in music history that scholars can point to the beginning of a particular style, but bluegrass would appear to be the exception to the rule. Mandolin player Bill Monroe from rural Kentucky had so much clout in the music business that some scholars have suggested that it was he who defined the sound which came to be known as bluegrass. He was certainly protective; Monroe is quoted as saying “the biggest job of bluegrass is to keep out what don’t belong in it.” Played initially in America's rural south, bluegrass was later adopted by the counter-cultural college kid scene in the 1950s and '60s. And today the music is flourishing all over the world in the most unlikely places. Rajan Datar is joined by Dan Boner, director of the Bluegrass, Old-Time, and Roots Music Studies programme at East Tennessee State University, who demonstrates how bluegrass works; writer and historian Tony Russell, whose publications on music include Rural Rhythm: The Story of Old-Time Country Music in 78 Records; and Dr Lydia Hamessley, professor of music at Hamilton College whose research concentrates on old-time and bluegrass music. She is the author of Unlikely Angel: The Songs of Dolly Parton. Producer: Fiona Clampin (Photo: Lester Flatt (right) and Earl Scruggs (left) perform with The Foggy Mountain Boys at the Grand Ole Opry circa 1960. Credit: Michael Ochs Archives/Getty Images)