Howlin' Wolf roared out of the electrified blues joints of Chicago in the early '50s, pairing his snarling-but-soulful voice with a succession of volcanic guitarists. Wolf's lascivious rasp soon filtered into the decadent strut of The Rolling Stones, while his feedback-tinged licks pointed toward the pummelling swing of Led Zepelin. And even long after punk's scorched-earth assault, Wolf's raw power continued to liberate outsiders, surfacing in both the primal howling of PJ Harvey and the filthy grooves of the Black Keys.