December 3-4, 1969. Keith and Mick stood at the same microphone at Muscle Shoals, lights dimmed, splitting a fifth of bourbon, and simultaneously sang the melodies and harmonies on the three songs that they had recorded over three days: "Brown Sugar," "You Got to Move," and "Wild Horses." That's your rock 'n' roll fantasy right there, pal. A six-piece band working in a tiny converted coffin factory across from an Alabama graveyard, on an eight-track...