Although I "discovered" Roy Buchanan when I was a blues-loving kid in the mid-'80s, the guitarist's first brush with something resembling fame came in 1971, when a documentary, The Best Unknown Guitarist in the World, aired on public TV. The documentary was about Buchanan, a blues-rock virtuoso whose gritty, distinctive technique inspired scores of guitarists, including Jeff Beck.

Because the reception in the mountains was terrible and full of static, I couldn't hear it clearly. But it sounded like a "new" Stevie Ray Vaughan song; the guitar playing and the vocals sounded like the late SRV, who had died five years earlier. I could make out some of the lyrics, which included stuff like "I've been gone too long." It as if the late SRV was saying howdy fromago this summer — in late July and August 1966 — the Beatles found themselves in a touchy situation. On July 29 of that year, a teen magazine called Datebook published segments of a nearly 5-month-old interview with John Lennon. Among the republished segments was this quote by Lennon: "We're more popular than Jesus now; I don't know which will go first — rock 'n' roll or Christianity."

David knew Graham, and he came to our Crosby & Nash show in London a couple of times and liked our harmonies and our way of going at it, and he asked us to sing on [his 2006 solo album] On An Island. In the process, we got to be pretty close friends. He asked us to sing at his concert