His death was confirmed by his son, James.
Dr. von Klemperer, an emeritus professor of history at Smith College, was one of a generation of refugee historians who helped lay the groundwork for modern German and European studies in the United States, a group that also included Hajo Holborn, Fritz Stern and Peter Gay.
A privileged child who came from a family of German bankers and industrialists, he had taken a leading role in demonstrations against Hitler as a student in Vienna before fleeing to the United States in 1938.
Dr. von Klemperer, the author of seven books, was best known for his 1992 work, “German Resistance Against Hitler: The Search for Allies Abroad, 1938-1945.”
On July 20, 1944, in the signature moment for the movement, Count Claus von Stauffenberg, a German Army colonel, placed a briefcase containing a bomb under the map table at Wolfsschanze, Hitler’s headquarters in a bunker in East Prussia. Hitler survived the ensuing blast, proclaiming divine providence, and set off a wave of executions of conspirators.
Dr. von Klemperer’s book explored the broader aims of the resistance movement and how its leaders — among them the aristocrat Helmuth James von Moltke and the theologian Dietrich Bonhoeffer, as well as diplomats and high-ranking military men — had made many contacts seeking support from the Western Allies.
“He really charted the foreign contacts of that group; that’s the importance of von Klemperer’s work,” Catherine Epstein, chairwoman of the history department at Amherst College and an expert on German history, said in an interview. “These were very nationalistic resisters. They wanted to have an independent Germany, did not want to be occupied by the Allies.”
Their outreach was thwarted by the Allies’ goal of unconditional German surrender and by a lack of trust in the resistance movement. Yet, for Dr. von Klemperer, their efforts achieved a higher goal.
“He attempted to show that there were indeed good Germans, and that they were deeply, morally offended by the Nazis,” said Allan Mitchell, who profiled Dr. von Klemperer in his 2011 book “Fleeing Nazi Germany: Five Historians Migrate to America.” “That’s what was most important to him.”
In “German Resistance Against Hitler,” Dr. von Klemperer wrote, “The determination of the German Resistance to reach the ‘greater world’ stands as an example for the many dissidents and freedom movements who in our day, still plagued by oppression, are appealing to the conscience of the world.”
Klemens Wilhelm von Klemperer was born in Berlin on Nov. 2, 1916, into what had been a Jewish family until his grandfather, Gustav, the director of one of Germany’s largest banks, converted to Protestantism.
Klemens’s father, Herbert, was the president of a company that manufactured locomotives, submarines and torpedoes for the German military.
That status and the family’s conversion mattered less and less after anti-Jewish laws were passed in 1933. In 1935, young Klemens joined his mother’s family in Vienna.
He studied history at the University of Vienna and, after Hitler’s annexation of Austria in March 1938, took part in student street protests. But by November, with his family’s property seized, he had fled to the United States. Eventually, members of his family were killed at Auschwitz.
He enrolled at Harvard under a program for refugee scholars, but his studies were interrupted by his service as an intelligence officer in the United States Army. After returning to Harvard, he received his doctorate in history in 1949 and soon joined the faculty at Smith, where he taught for 37 years.
Among Dr. von Klemperer’s other books are “A Noble Combat: The Letters of Shiela Grant Duff and Adam von Trott zu Solz, 1932-1938” (1988), about the romantic relationship of a British woman and a German diplomat as they struggled with their concerns about the Nazi regime, and “Ignaz Seipel: Christian Statesman in a Time of Crisis” (1972), a biography of an Austrian priest who became chancellor in the 1920s.
Besides his son, Dr. von Klemperer is survived by his wife of 59 years, the former Elizabeth Gallaher; a daughter, Catharine Utzschneider; and four grandchildren.
Three years ago, Dr. von Klemperer’s memoir, “Voyage Through the 20th Century,” was published.
“I was not an extraordinary person, but I did live in extraordinary times,” he wrote, “and my small mission was somehow to make sense of it all.”
