Book excerpt: In 1969, at the Ryman Auditorium in Nashville, Tennessee, American music changed for ever. Bob Dylan, the most daredevil spirit of the rock era, took the stage for the first time with Johnny Cash, country music superstar. This show at the temple of country music, The Grand Ole Opry, was the most public evidence of a collision of styles which first occurred in the mid-1950s and has sent shockwaves through American music ever since. Country Rock, as played by the Byrds, the Eagles and Gram Parsons, was to become the dominant style in American music during the 1970s.