So much has been said and written about the Beatles -- and their story is so mythic in its sweep -- that it's difficult to summarize their career without restating clich+¬s that have already been digested by tens of millions of rock fans. To start with the obvious, they were the greatest and most influential act of the rock era, and introduced more innovations into popular music than any other rock band of the 20th century. Moreover, they were among the few artists of any discipline that were simultaneously the best at what they did and the most popular at what they did. Relen...