The Beatles' first excursion to the United States, from February 7 to February 21, 1964, was an epochal moment in American culture. It was a musical earthquake that defined music going forward and a cultural youth quake that defined generations to come. That fourteen day window not only solidified the Beatles' careers, it reshaped our culture, and nothing thereafter was ever the same. It was as if someone flipped a switch, and from February 7 on,...