Bill Monroe

Kentucky-born mandolinist and bandleader known as the father of bluegrass, who led the Blue Grass Boys through the genre's founding lineup years. His 1946 recording of "Blue Moon of Kentucky," cut for Columbia with Lester Flatt and Earl Scruggs both still in his band, became the music's foundational waltz -- and, eight years later, the song Elvis Presley converted into a 4/4 blues-rock B-side that helped invent rockabilly.