In the early morning hours after John Lennon was shot and killed, people began gathering in front of the Upper West Side apartment building that he shared with his wife and their young son. For more than a week, from everywhere and of all ages, they came to keep a vigil. Watching the local news channel, I hear them referred to as Beatle fans. But what I see are mourners. Crowded together, hemmed in by police barricades, they weep and hold candles and signs, cleaving to the spot where Lennon left this earth.