Dr. Stern is Professor Emeritus and former provost of Columbia University.

In my work as a historian in the postwar years, I was only intermittently aware of the ties between my life and my studies; fully committing myself to the historian’s craft, I knew that while Clio allowed for many ways of serving her, all of them demanded a measure of detachment — enlived, one hoped, by empathy and a disciplined imagination…. Perhaps I didn’t quite anticipate that when one fully lives with the upheavals of one’s time, one comes to see the past in new, more complex ways. Also, I realized more and more that the lessons I had learned about German history had a frightening relevance to the United States today. And gradually I acquired another German life, parallel and subordinate to my American life. I came to live in two worlds simultaneously, learning from both.

As I came to know something about my third and fourth Germanys [the BRD and DDR], luck and predisposition to civic action made me “an engaged observer”…. I was intermittenly drawn from my study and classroom onto the fringes of political life in both Germany and America, and counted myself lucky to be able to see and respond to historic events that were shaping the new Europe in its new relations to the United States. I still thought of this as the public work of history….

Life and study have persuaded me of the openess of history. There is no inevitability in history. Thinking about what might have happened, what could have happened, is a necessary element in trying to understand what did happen. And if, as I believe, individual acts of decency and courage make a difference, then they need to be recorded and remembered. …

The Germanys I have known, however partially and fleetingly, together portray the end of a historic Europe we cannot return to, and the start of a more modest, cohesive, and peaceful era for the continent. In recent decades we have seen wondrous, miraculous reconciliations in Europe, themselves perhaps intimations of partial homecoming. So the history of these five Germanys can be read as a text for political and moral lessons, as a drama in dread and hope. We owe the victims of the last century’s descent into an inferno of organized bestiality and enduring, awed memorial: a prudent vigilance — and the knowledge that the bacillus that killed them did not die with them.