Rock music has always thrived on reinvention. Many of the early rock tunes were covers of blues and R&B songs. Rock guitarists were notorious for borrowing licks from blues songs and powering them ...

The Beatles, from left, John Lennon, George Harrison, Ringo Starr and Paul McCartney appear in Liverpool, England on July 10, 1964, for the premiere of their movie "A Hard Day's Night." (AP Photo) ...