"He's a musical genius," Neil Young said of Stills in a 2000 interview. He should know. The two have been bandmates and competing lead guitarists on and off since 1966: in Buffalo Springfield, the supergroup Crosby, Stills, Nash and Young, and the short-lived Stills-Young Band. But those groups' ego-and-drug dramas have obscured Stills' prowess as a musician — he played nearly every instrument on Crosby, Stills and Nash's 1969 debut — and especially as a guitarist. In Springfield and CSNY, Stills challenged and complemented Young's feral breaks with a country-inflected chime. And a continuing highlight of CSNY shows is Stills' acoustic picking in "Suite: Judy Blue Eyes" — a paragon of unplugged beauty.