October 9th marked the fiftieth anniversary of John Lennon's birth. December 8th will mark the tenth anniversary of his death. It is somehow fitting that the two dates will proceed forever down the ages, each inspiring commemoration as they simultaneously reach round numbers, the sad reminder of a death following hard upon the celebration of a life.

Lennon's death still reverberates with stunning force; it has lost none of its impact over the past decade. For anyone who cared about the Beatles and Lennon's individual vision and political activism, his impulse to experiment and his willingness to speak the unwelcome truth, the world is simply a less enjoyable, less engaging place without him. For those inclined to speculate, it is easy to imagine that his presence could have blunted the hard edges of the Eighties, that his humor, intelligence and sense of integrity could have proven a strong tonic for the spirit in those cynical times.

With Double Fantasy, the album he and Yoko Ono released in 1980, Lennon was clearly ready to return to public action after a five-year immersion in family life. How would his music have evolved in the Eighties? Interested in film all his life, how would he have responded to the rise of video? Lennon's uncompromising voice has been sorely missed during the censorship controversy of the past five years. Wouldn't it have been amazing to see John Lennon walk onstage during Live Aid? And in the decade of comebacks and reconciliations, could the Beatles really have resisted a reunion if Lennon had been alive? Would he have wanted such a thing? The loss of one life can change the course of a whole world.

On October 9th, Lennon's life was celebrated in a brief ceremony, called Imagine All the People, at the United Nations. After being welcomed to the UN — "this House of Peace" — by Marcella Pérez de Cuéllar, the wife of UN secretary general Javier Pérez de Cuéllar, Yoko Ono read a prepared statement, played a tape recording of Lennon, in which he urged the world to recognize "the choice we have in front of us: war or peace" and then broadcast the song "Imagine" over more than 1000 radio stations in 130 countries to an audience of approximately a billion listeners.

Several hundred UN diplomats and delegates, journalists, friends of John and Yoko's and other guests gathered in an auditorium at the UN for the ceremony. "The dream we dream alone is only a dream," Yoko said during her introduction, invoking the more mystical aspect of her and Lennon's shared sensibility. "But the dream we dream together is reality." Indeed, like Martin Luther King, John and Yoko had a dream.

In both its scale and its simplicity, the event was an eminently appropriate tribute to Lennon, a man who never hesitated to exploit the platform he enjoyed in the media to try to change the world. His blunt messages — "All You Need Is Love," "Give Peace a Chance," "Power to the People," "War Is Over If You Want It" — were essentially advertising slogans in the service of social betterment. Even the tape of Lennon that Yoko played was moving in the directness, the plain-spokenness, even the naiveté, of its appeal.

"You have the power, you know, you have the vote," Lennon said, speaking in his characteristically natural, unforced cadences. "Just show your neighbors that you're trying to be peaceful, however hard it is. It's hard for us all. Just pass the word around.... Just have one word, Peace, in the window. And even if you don't exactly know why you're putting it in the window, it can't harm you. And then you'd come across other people that have put Peace in the window. They're all hoping for peace. We're all together on this thing. We all want peace, whatever sort of job we have."

We may all want peace, but ten years after Lennon's death, peace has proven as elusive as ever. Looking ahead, it is difficult to be optimistic, and it is difficult to assess the true quality of Lennon's impact on the world he fought so incessantly to improve. Sitting in the living room of the apartment she shared with Lennon for many years in the Dakota, in New York, Yoko Ono discussed the legacy of John Lennon on the day after the ceremony at the United Nations. Even Yoko had to admit that, at least in the years immediately following her husband's death, it seemed as if much of their work had come to naught — though, in her view, that work bore fruit eventually and will continue to.

"John was saying in 1980, 'The Eighties are going to be a great, great decade, a fantastic decade,' " Yoko said. "Mainly to project positiveness — and I was saying that, too. But fans would write to me, saying, Well, John said the Eighties were going to be great, but what's this?' For one thing, to start the decade, John died. Then what happened was — I think it started with Band Aid and Live Aid. We had "We Are the World," Hands Across America, Amnesty International — all of these big things started to happen.

"Those things were the results of the grass-roots movements of the Sixties," she continued. "The memory of that must have been there and started to blossom. Then there was a peace conference in Moscow. Then Gorbachev and Reagan shook hands. Then at the end of the Eighties — as if somebody was making a point to do it within the Eighties — suddenly the Berlin Wall disappeared, Eastern Europe was freed. I mean, it's incredible!"