Bebop ('40s) + R&B ('50s) = Hard Bop. Graduates of the Art Blakey Academy. When 1940s Bebop began to burn out and 1950s R&B filled the void, Hard Bop emerged and prevailed, before it grooved into 1960s Soul Jazz. Seems like half these cats played with the great Blakey's ever-shifting "Jazz Messengers" ensemble. Compilation includes 15 tracks by many of the heavyweights — and one slick chick.