"Surreal and also satisfying" is how Minneapolis writer Jack El-Hai describes his time in Budapest, hobnobbing with actors Russell Crowe and Rami Malek.

Those two Oscar winners (Crowe for "Gladiator," Malek for "Bohemian Rhapsody") are about two-thirds done filming "Nuremberg," an adaptation of El-Hai's book, "The Nazi and the Psychiatrist." They play the title roles: Crowe is Hermann Göring, one of Adolf Hitler's top officials, and Malek is Army psychiatrist Douglas Kelley, hired to determine if Göring was fit to stand trial for war crimes.

So far, El-Hai has taken long walks in Budapest, taken in the applause from cast and crew when he was introduced as the man without whose book the movie would not be happening and marveled at sets that re-create the courtroom where the Nuremberg trials took place in 1945 and 1946 and the prison where Göring was housed.

"It's been the most fun work trip I've ever been on," said El-Hai, whose stay in Budapest was extended a couple of days while he observed filming and answered cast and crew questions when they came up. "I asked a lot of people involved about how they think it's going and everyone says it's going well."

The book's journey to the big screen has been long. Its writer is the first to acknowledge that his nonfiction book was not a big seller when it was published in 2013. But Hollywood hopped on "Nuremberg" even before it was published, having noticed the story when El-Hai "test-drove" it with a magazine feature about Göring and Kelley. The now-defunct production company that purchased the first option on the book renewed it multiple times in the intervening years.

The enduring attraction of the tale? Its two strong central characters.

"I always refer to it as King Kong vs. Godzilla in a fight to the death," joked El-Hai (who was unaware that "Godzilla x Kong: The New Empire" had just opened).

With writer/director James Vanderbilt finally at the helm, "Nuremberg" was set to film in spring 2023, but strikes by the actors and writers unions cut it off.

As filming drew near, Malek reached out to El-Hai for more information about Kelley, and El-Hai visited the set to observe and be a resource.

"I know a little about how [Malek] sees the character," said El-Hai. "The movie covers only some of the years that are covered in the book — the run-up to the first Nuremberg trial and a tiny bit afterwards. But Rami, who had read the book, was interested in talking with me about Kelley's early and later years."

That was fine by El-Hai, who's keenly aware that books and films tell stories in different ways.

"What I'm looking for is a creative person who can really focus on a tough conflict that's in the story and pull forth from that the best dramatic possibilities," said El-Hai. "I didn't hope a movie based on 'The Nazi and the Psychiatrist' would be like this or like that. I wanted to see what it would become and I'm very happy with what it is becoming."

El-Hai believes the "remarkably easygoing, gentle" Vanderbilt is responsible for the positive vibes he detected on the set: "I was a little, I won't say apprehensive, but I wondered what this world was going to be like. But once I got to the studio Monday morning, people were all so welcoming and kind."

There will be more trips to see how others reimagine El-Hai's work. "Nazi" also has been adapted into a play, "Sense of Decency." El-Hai and his wife, Ann Aronson, will attend opening night April 20, at California's North Coast Repertory Theatre.

Meanwhile, El-Hai's "The Lobotomist" also was sold to Hollywood before it was published in 2005 and the writer said there's a script in place that may finally make it before cameras.

The prolific nonfiction author has written five books, including Minnesota-set "The Lost Brothers," and dozens of magazine articles. He publishes the free monthly newsletter Damn History, which focuses on popular history, and he blogs the behind-the-scenes stories of his work at el-hai.com.

El-Hai is currently at work on two more books that could interest moviemakers: "Face in the Mirror," due next year, is about a young man who received a full-face transplant at the Mayo Clinic. And the tentatively titled "The Case of the Autographed Corpse" is about an Apache medicine man who was wrongly convicted of murdering his wife and who reached out to "Perry Mason" writer Erle Stanley Gardner for assistance in helping to overturn his conviction.

No release date for "Nuremberg" has been announced but, given the talent involved, Oscar prognosticators are already including the film in early predictions for next year's awards, which suggests it could reach theaters before the end of the year.