Terry Callier. Childhood friend of Curtis Mayfield. Signed to Chess Records' Cadet imprint -- the psychedelic soul subsidiary that gave us Rotary Connection. His album What Color Is Love is a cosmic folk-soul masterpiece that practically nobody heard in 1972. He quit music, got a computer science degree, raised a daughter. Then in the 1990s, British rare groove DJs found his records and started a revival. He returned to stages he'd never played, singing songs he'd written decades earlier to audiences who'd been waiting their whole lives.