On New Year's Eve, 1970, Paul McCartney told his lawyers to issue the writ at the High Court in London, effectively ending The Beatles. You might say this was the last day of the pop era. The following day, which was a Friday, was 1971. You might say this was the first day of the rock era. And within the remaining 364 days of this monumental year, the world would hear Don McLean's "American Pie," The Rolling Stones' "Brown Sugar," The Who's "Baba...