Ken Burns was in his studio working on the final edits of a forthcoming documentary film series on the American Revolution when he learned on Tuesday that the historian William E. Leuchtenburg had died at 102.

“I had to get up and go be by myself for a while,” Mr. Burns said in an interview. “Everything just crashed to a halt.”

In his view, Mr. Leuchtenburg was “one of the great historians, if not the dean of American historians in the United States, for his work on the presidency.”

For more than 40 years, Mr. Leuchtenburg was a close adviser and friend to Mr. Burns, appearing in three of his documentaries — “Prohibition” (2011), “The Roosevelts: An Intimate History” (2014) and “Benjamin Franklin” (2022) — and consulting on many more.

The Times spoke to Mr. Burns on Wednesday about Mr. Leuchtenburg’s career. His observations, lightly edited and condensed for clarity, are below.

A Friendly Correspondent

He would send me notes all the time. My files are filled with these notes with little schoolboy handwriting. It reminded me of the way I wrote cursive when I was in the eighth grade. I just want to imagine that he had a filing system that looked like the cavernous place at the end of “Citizen Kane” or “Raiders of the Lost Ark,” because he could not have had so many references at his hand. He would just bring them up. It might be baseball, which he and I both passionately loved. It might be jazz. It might be World War II. Obviously the presidency. Vietnam. Really all of the kinds of things that we’ve done. He had an interest in what we were doing and how we were doing it that made him an extraordinarily helpful contributor.

Baseball and Booze

He made particularly important contributions to our history of baseball, to the Second World War, to our Prohibition film — in which we learned personally from him the very, very complicated internal dynamics, not just about what took place in Prohibition, but his own personal family life in which both his parents were alcoholics. And so the repeal for him was not a good thing. He also understood, hilariously and intimately, the sexual revolution that was going on in the 1920s among women, and just flat-out said that people discovered the clitoris. And that was, like, whoa!

Picturing the Depression

He was a storyteller. All you need to do is go into the fifth episode of the Roosevelt series and look at his concise way of explaining what it was. He first talks about filling up a stadium with people and then emptying it and then filling it up again. And if you did this over and over again, you would get the number of people who had gone out of work. It was just such a vivid description.

Working Without Him

I’m going to cry talking about it, but it’s just this gigantic and unfillable hole. He taught us well, though. He’s imparted not just facts, but attitudes and relationships and methodologies that we’ll save. We’ll be poorer for not having Bill to come and look at a rough cut of something that he shouldn’t know anything about but then inevitably knows a ton. We’ll muddle through.