When the Beatles broke up in 1970 in a welter of lawsuits and recriminations, the sixties were ending as well—in spirit as well as by the calendar. Bloodshed and bombings on campus, the harsh realities beneath the facile hopes for a "Woodstock nation," the shabby refuse of counterculture communities, all helped kill the dream.

What remains remarkable now, almost 20 years after John Lennon started playing rock 'n' roll music, more than a decade after their first worldwide conquest, is how appealing this dream was; how its vision of the world gripped so much of a generation; how that dream reshaped our recent past and affects us still….

[The] impact of the Beatles cannot be waved away. If the Marx they emulated was Groucho, not Karl, if their world was a playground instead of a battleground, they still changed what we listened to and how we listened to it...