But it was the sixties, and rock and roll, that elevated this age-old phenomenon to a new scale of popular intensity. At Watkins Glen, New York, in 1973, the Grateful Dead played to some 600,000 people, a crowd that stretched over two miles from the stage. It was an occasion that still stands as the largest rock concert in history. (Woodstock, by comparison, hit roughly 400,000.) “We have four or five times as many people here as we have at our [auto] races,” said the county sheriff, “and we are getting less than half the trouble. These kids are great.” I can scarcely imagine that many people in one place, much less that many people in one place with their minds trained on a single object. If you want to try, consider that the average sports arena holds only 50-60,000—and multiply by ten.

Who knows what unseen influence such gargantuan incidents might have had on the culture at large? Is consciousness a cumulative thing? One person meditating alone can have a tangible effect in a room. Even the Trips Festival of early '66, the largest-ever Acid Test, involved only 3-5,000 people. Up until that point, Phil recalled, “nobody could have guessed that you could give thousands of people acid in one room and not have it blow up from the psychic energy . . . the cords of our equipment were literally jumping out of the wall sockets.” So, 600,000 at Watkins Glen? What unknown miracles of consciousness might have broken forth then, subterranean, invisible?

Of course, the Grateful Dead weren't the only sixties band to work miracles. How about the Beatles, whose fans, admits Grateful Dead publicist Dennis McNally, “made the enthusiasm of Deadheads look quite demure”? If the Dead can be measured on the Richter scale of their psychic influence on large numbers of people, then surely, so can the Beatles. And by this standard, are the boys from San Francisco even in the same league as the lads from Liverpool? As far out as the Dead were, they never broke free of a relatively marginal counterculture. The Beatles, on the other hand—everybody loves the Beatles. “There was an alchemy in the way they came together that made two plus two equal not four but forty,” journalist Mark Hertsgaard writes. They gave the words “come together” a whole new meaning.

In the summer of 1965, when the Grateful Dead (then known as the Warlocks) were still earning their first stripes in the bars and clubs of the San Francisco peninsula, the Beatles played not the largest, but the first-ever concert held in a sports arena in the U.S., at Shea Stadium in Flushing, New York. This was ten years before I was born (yep, I had to watch it on DVD). But in spite of all the decades in between, I could hardly believe what I was seeing. Here were four kids barely into their twenties, caught in the midst of a passion that had everything—and perhaps very little—to do with them. They were at the eye of a cultural hurricane; how could four people alone cause such lunacy? To see otherwise decorous young women unleashed as hysterical, sexual beings—en masse—would have frightened me if it hadn't so furiously held my attention. The marvelous thing was, none of it seemed to be going to the Beatles' heads, though it did go to John's elbows, with which he played a madcap keyboard solo. “We like lunatics, it's healthy,” he quipped. Beatlemania got so big, so fast—bigger than they could handle, really. But for some mysterious reason, they didn't have to handle it, that pressure high enough to launch Paul's Hofner bass to the moon. They just climbed aboard and rode it straight to the center of the unexplainable. At Shea Stadium, I could see the boundaries between them broken and obliterated; and them, sweating, reeling, singing, helplessly amazed. It set the crowd on fire with a kind of innocence I'd never seen at a Dead show, another kind of wonder.

There were 55,000 people there, screaming so loud the Beatles could barely hear themselves playing. At least Deadheads listened to the music; Beatles fans couldn't even get to the first note without succumbing to something like a virus that made them yell till they were hoarse, some sort of “emotional epidemic.” It was as if they were ripping holes clean through the walls between them: Who knows the depth of impact this had? How about when the Beatles first performed on the Ed Sullivan show in February 1964, a year and a half earlier? Seventy-three million people were watching. That's forty percent of the U.S. population, roughly equal to the total number of televisions in the country that year. During that hour, precincts across the nation reported the lowest crime rate in half a century—even thieves, thugs, and malcontents took a timeout for the Beatles. Billy Joel thought, “This can be done. I can do that.” He was fifteen. Billy Graham, forty-five, even broke the Sabbath to watch.

Who knows how they did it. “Probably not since Shakespeare has so much intellect been invested in explaining something so simple,” Robert Burt writes in The Beatles: The Fabulous Story of John, Paul, George, and Ringo. “The Beatles were four guys in a pop group who made happy music and gave everyone a good time for a few years.” A few years? The Beatles were still topping the charts at the turn of the millennium with “1,” their album of singles. It had to be more than that. How did they manage to be so fully with each other, in such a way that everyone felt it? Not like the Dead were, not as shamans or warlocks, but as ordinary young men? Simultaneously down-to-earth and larger than life, the Beatles swiftly took on the power of a tidal wave in mass consciousness. “They are very like children in many ways,” producer George Martin said. “They love anything magical.” And the magic of being together, with unusual joy and uncommon trust, fed their music with irrepressible enthusiasm and unceasing originality. As they evolved and matured, a whole generation grew up with them. In the process, they helped chart a course through the changing tides of a turbulent era. From Motown to R&B, straight-ahead rock and pop to wide-ranging psychedelia, the Beatles spanned what seems like eons in a few short years, tugging an emerging youth culture right behind. That speed of change was almost too much to take, but take it young people did—and so did many of their parents. “It was up to you—which is to say, all of us—to make changes, and you could do it,” Hertsgaard writes. “That message resonated deeply and powerfully in the mass psyche, for it put people in closer touch with their higher selves and made them feel part of a larger project of human renewal. The Beatles, in short, brought out the best in people.”

Whatever their secret was, Paul McCartney still has it in spades. “I don't feel like finishing or stopping,” he said recently, after his 2002 “Back in the U.S.” tour, his first in the United States in nearly ten years. And this time, I had the rare fortune to see him in person. Just into his sixties, his talent, sparkle, and poise all seemed only to have grown, captivating whole new generations of fans with the same enchantment that made the Beatles what they were. It seemed impossible; I still can't quite get my mind around it. Even Jerry Garcia, gallant ship's captain, broke slowly under the pressure of a lifetime as a mythic hero, losing the fight after nearly twenty years of heroin addiction. Paul, by contrast, was more in command than ever, playing and singing like a man half his age. Out in front of a band that was tearing and jumping fresh all over his Beatles and Wings songs, he boosted everything he touched into a sort of intimate glory, whether or not you even knew the tunes. Little Gen-Y kids were bursting like popcorn; college students, parents, and grandparents were crying, gasping, dancing, and basking in the sheer generosity of it all. One fan held up a sign, “NYC 1965 Shea Stadium,” and somehow I, as a twenty-eight-year-old, knew why—I felt the same, at the hands of Midas, exhilarated for the first time all over again.

“Listening to his music,” Gen-X actor John Cusack remarks on Back in the U.S., a DVD chronicling this same tour, “is part of the whole fabric of becoming conscious.” The most surprising thing of all is that McCartney is no mere footnote to history, his music no romantic allusion to the timeless relevance of sixties sensibility. Rather, his influence is still active today, still pointing forward in the year 2004. Just last year, for example, he took the residents of Copenhagen somewhere they'd never been before. A Danish friend who lives in Østerbro district, near the Idrætsparken where Paul's concert took place, told me the story: “After the show was over, the city was saturated with affection,” he said. “The whole place was humming. We've never had that kind of experience in Denmark, at all.” Crowds that spanned the generations filled the streets, he described. Retailers and merchants across Copenhagen, like the bicycle shop on his corner, opened their doors and put out tables, serving beer and refreshments. Most of the city, it seemed, was out until four in the morning, singing Beatles songs, laughing. “People were just drawn to each other. They gathered in groups. The whole town was one big meeting place.” Though the boomers among them felt a swell of nostalgia for the good old days, it was not accompanied by the usual sense that life was better then than it was now. There were no lamentations for a past lost to the cruelty of time, no sad ruminations on a fall from grace. Instead, he concluded, “It was completely fresh. There was no wrong in this, everything was right. Life is good and love is sweet.” It was as if Paul made everyone young again—not in imagination but in fact, transformed inside their own bodies.

When I was eighteen and a bit younger myself, I went to sing in Russia on a sort of musical peace mission with my United Methodist choir. By then, I was already into the Dead; I remember playing “Uncle John's Band” in Red Square on a five-dollar Russian guitar. Ten years later, in May 2003, Sir Paul put on his first-ever show in Russia, also in Red Square. Meeting with the ex-Beatle before the concert, Russian President and ex-KGB agent Vladimir Putin “confessed that in Soviet times the Beatles were considered 'propaganda of an alien ideology,'” CBS reported. When asked if he'd listened to the Beatles anyway, Putin replied, “Yes, of course—it was wildly popular. . . . It was a taste of freedom; a window on the world.” Beatles music, it appears, was strong enough to puncture even the Iron Curtain. And for a hundred thousand Russians—some of whom fit into the storied quadrangle in front of the Kremlin, the rest of whom gathered behind police barricades to listen—this was the chance of a lifetime, the chance to see a hero who, for decades, was only accessible by bad radio or bootleg. “Next stop the moon,” said Paul. And who would stand in his way?

“I like the fame because of what you can do for charity,” Paul comments during Back in the U.S. “And I think if your heart's in the right place, you can do a lot of great stuff.” Yes, indeed, and he has. As for Jerry, whose creative incandescence will undoubtedly stand the test of time . . . to be honest, I'm ashamed of him. “Fame is an illusion,” he complained in one of the last interviews he ever gave, before a junkie's isolation became a dead man's coffin. “It's very hard to take the fame seriously, and I don't think anybody wants me to. What's it good for?” I guess we'll never know. But what are the moral implications of being a hero? If the power of consciousness itself can elevate whole groups of people so dramatically, who's to say it can't push them down with equal weight? “The Dead do something no other musicians of their stature or influence can,” observed the Village Voice in 1987. “They suggest the possibility of utopia in everyday life . . . indirectly nurture humanity, goodness, joy, truth, and solidarity among their devoted audience. . . . [They] do no less through their music than espouse the quaint notion that art can save your life.” Isn't it ironic, then, that Jerry couldn't save his own from whatever demons beset him?

Jerry's bandmate Phil once said, “we were on the tip of the arrow of human consciousness flying through time.” Perhaps the Grateful Dead, or at least their ambivalent leader, fell off that arrow years ago, while Paul fashioned his into a jet, somehow managing to keep the wind in his hair. But what if that arrow itself—the arrow they both pulled and fired—yet flies, gathering speed, about to break the sound barrier? Back at the Trips Festival in '66, back in '67 when the Beatles released Sgt. Pepper's, a mass revolution in consciousness seemed just around the corner. Might it still be there waiting, working even? I don't know. Maybe none of us do, yet. Nevertheless, merely the potential these bands suggested—the potential makings of a more lasting, collective entry into higher states of holistic awareness—is enough to make us think twice about who we are and what is possible. Think, and wonder, as we walk out the amphitheater gates after the last notes of the encore, wrapped in a blanket or two, looking at the sky, asking questions the Dead and the Beatles made so compelling.