There's a good reason why the King of Rock 'n' Roll couldn't stop swiveling his hips: His music swings with soul. His '50s hits “That's All Right” and the haunted “Mystery Train” are grooving rockabilly showcasing his brash musicianship. In the '60s, this stylistic chameleon adopted a big, absurdly romantic baritone and excelled at lush, dramatic ballads like “It's Now or Never.” Toward the decade's end, Presley re-embraced pure rock with “Suspicious Minds”—a galloping, desperation-stained masterpiece reflective of his late-career love for Southern soul.