Starting decades ago, each springtime, I would watch some of my fellow alumni in Harvard Yard as they marched in celebration of their sixtieth reunion. Most of them walked confidently, though somewhat guardedly, on their own; some of them used canes; a few sat in wheelchairs as they were pushed along.

These men all impressed me the same way: They struck me as awfully old. That made them different from me, different enough to make it seem unlikely that I could ever look quite like them.

Last week, however, it was I who processed among the sixty-year reunioners. My class of 1951, had reached the milestone that for so long had appeared remote to me. Now we had become the ancients, former boys who had progressed to old age.

A lot of us were missing from the reunion — some because of disability or schedule conflicts, but many because they had died. To a few, death had come in the months just before we convened.

This fact seemed immense to me.  Because I had been appointed chair of the memorial service committee, death had been on my mind. During the service, classmates would be reading aloud the names of those who had died in the last five years.

Long ago, the class of 1951 had taken on a premature familiarity with death. Six of our classmates had died fighting in the Korean War. One of their number had won the Congressional Medal of Honor.

Among the other 1100 or so classmates, I have lost several close friends. That reality posed a question that continues to haunt my psyche: Why them and not me?

Even though they have passed on before us, the living, I still regard them all as belonging to us. They may have preceded us in the outcome that awaits us all, but they have not lost the respect and affection that we feel for them.

As the names of those who died relatively recently were read at our memorial service, they evoked a variety of memories; brief impressions, long-ago conversations, or shared experiences that I continue to treasure.

During the months of planning, the twenty or so members of the central reunion planning committee were full of energy and good humor. They came to each meeting eager to devise a series of rewarding reunion activities.

I liked being with classmates in this situation. Sitting and conversing made me feel that we belonged together. After all, we had shared the passage of sixty years, six decades of an incredible range of personal adventures and misadventures and unforeseen changes in our nation and our world.

Many members of our large planning committee showed some signs of physical wear and tear.  It was painfully clear to me that some would not have many years left. However, they had come to contribute their ideas and volunteer their work to ensure a good reunion for all.

True to the educational ideals that had animated us long ago, we arranged for several speakers from the faculty who would talk about the latest scholarship. The subjects would include stem cell research, current economics, and the arts.

One of this year’s innovations was particularly welcome. For the first time in sixty years, our Harvard class reunion would be shared with our Radcliffe contemporaries. These women had shared our classes, but not our institutional life—a situation very different from that of today’s Harvard undergraduate women.

An important product of the committee was the class report. This volume was sent to all 51’ers, many of whom provided late-breaking accounts of our lives. By way of further history-making, the book included both Harvard and Radcliffe classmates.

A wonderful suggestion led to the inclusion in the memorial service of the poem “A Walk By the Charles” published, two years after graduation, in the New Yorker by Adrienne Rich, of the Radcliffe class of 51.

On Commencement Day, I joined classmates in the parade of classes into Harvard Yard. I processed despite coping with one knee made gimpy by arthritis. Whether my efforts to hide this new handicap succeeded I do not know, but it seemed to me an occasion for marching straight and tall.

Realistically, I expect that before long we will lose quite a few of our members, perhaps me among them. That sober thought occupied my attention as we planned this celebration.

But regrettable as it remains, and completely mysterious as well, dying seems to me perhaps the most important thing we ever do. Of course, for almost everyone it’s not our doing but what is done to us.

I don’t look forward to that event but facing it realistically seems to me far better than the alternative. When it comes for all of us current classmates, it will arrive at the end of long lives. And that is something to be grateful for.