Together with brother Charlie in the late ’30s, Monroe’s cross-pollination of traditional Celtic reels and southern American gospel assured him immortality as the founding father of bluegrass. With frenzied tempos, vaulting vocals and classic mandolin-guitar-fiddle-bass-banjo recipe, the Bluegrass Boys were pivotal in dragging hillbilly music into the US mainstream. His three-decade Decca career includes “I’m Blue I’m Lonesome”, “Raw Hide” and moving ode to his mentor “Uncle Pen”, while “Blue Moon Of Kentucky” was the one that prompted young Elvis to jump truck and head for Sun Studios.