In a 2018 volume of the German Yearbook of Contemporary History devoted to new research on Hitler, the editors Elizabeth Harvey and Johannes Hürter identified a recent “Hitler boom,” an unexpected increase in German research into Hitler beginning around 2013. But they’re wary of ascribing that upswing to public concerns. Academics, Harvey said, are largely not responding to “the worrying upsurge today of right-wing extremism, anti-Semitism, racism, right-wing populism, extremist leader figures” by thinking, “Right, I’m going to go write a better biography of Hitler to cure that.”

Indeed, professional historians are wary of drawing too many parallels between Hitler and authoritarian-minded present-day leaders. “History,” Matthäus said, “is probably more complex than these analogies would like to have it.”

Simms shares that view. “I don’t think there are any simple partisan points you can make today drawing on the findings of these books,” he said. “If there’s a comparison or a lesson, it’s to take seriously and look closely at what people say and what they argue before they come to power, and not to assume they will be tamed by the structures.” In writing about Hitler’s furious obsession with German emigration to America, Simms (who is British) did include one reference to the contemporary landscape: “The president is mentioned in the book, but only in the context that his grandfather, Frederick Trump, was one of those Germans that left Germany,” he said.

Simms is a political scientist and a professor of international relations; this is his first biography and his first book to focus on World War II. A significant motivation was personal: “My mother is German, and I grew up for quite a lot of my childhood in Germany,” he said. “My grandfather served in the Second World War on the German side.”

Longerich — whose previous books include biographies of the Nazi leaders Heinrich Himmler and Joseph Goebbels , as well as “Holocaust: The Nazi Persecution and Murder of the Jews” — has personal reasons for his interest as well. “Of course, you ask yourself: Why are you doing this?” he said. “Why are you so obsessed with this period?”

One reason, he said, is that he was born in Germany only a decade after the war ended. “My teachers actually served in the Wehrmacht. My history teacher was a former SS man. It’s difficult to see, the elderly people you know were actively involved in this system.” That difficulty, for him, turned to curiosity over “how rapidly the democratic Weimar Republic, center of modern culture, could turn into a dictatorship — and how quickly this dictatorship could be transformed, again, into a relatively normal democratic society.”

Academic caution aside, that curiosity isn’t detached from action; Longerich and Simms have both joined the growing ranks of historians speaking publicly about threats they see in contemporary society. Longerich helped lead a 2012 German parliamentary commission examining anti-Semitism in the country, and Simms is the president of a think tank, the Project for Democratic Union, that supports the constitutional creation of a single European state.

“For historians working on the history of National Socialism,” Elizabeth Harvey said, there’s “a feeling of obligation to intervene in current debates.” The timing of history is delicate, and the life of Hitler remains one of the most incomprehensible examples of how quickly the touch of the wrong person, at the wrong time, can shatter an order that appeared stable. “It was unimaginable,” Longerich said, “how the world I grew up in, only 25 years before, could be so different.”

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