This harmonica pioneer helped fashion the thick, evocative textures of Chicago blues for the likes of Muddy Waters and others, but he was also a vibrant bandleader in his own right. His early-'50s singles, such as “Straighten Up, Baby,” had a powerful rock ‘n' roll authority, and later sessions, like 1984's High Compression, delivered funked-up R&B arrangements of his old mainstays, like “Superharp.” When Cotton shared top billing with Waters—as on 1977's live recording Breakin' It Up, Breakin' It Down—the locomotive power of the Chicago sound was given a fresh jolt of energy.