Long before he began stirring up a smoldering pot of sonic gumbo with his spooky, swamp-psychedelic brand of New Orleans R&B, Dr. John the Night Tripper was Crescent City studio pro Mac Rebennack. That's the answer to the question posed by the collection WHO WAS MAC REBENNACK?, a 22-track anthology documenting the work Rebennack did as producer, pianist, guitarist, and songwriter, both under his own name and alongside the likes of Frankie Ford and Huey "Piano" Smith.