Edward Serotta glided around the room of Holocaust survivors and their families like an impresario, checking that they had enough food and drink and company. He sat with some, patted others on the back, endured some kisses and made sure that this monthly meeting at Vienna’s Jewish community center went smoothly, even as Viennese police kept guard outside, just in case.

About 80 people came to this pre-Rosh Hashanah gathering last month of Café Centropa, an outgrowth of Mr. Serotta’s singular project and achievement: Centropa, the nonprofit he built to document vanished Jewish life in Central and Eastern Europe.

With the help of dozens of researchers and his countless trips to the region, Mr. Serotta and Centropa created a digital archive of 1,230 interviews conducted in 20 European countries, totaling some 45,000 pages of testimony. The archive includes more than 25,000 photographs.

“And every one of them comes with a story,” Mr. Serotta said. “The Holocaust is mankind’s single greatest crime, and while there are witnesses to it, those stories should be told and recorded. But there is another chapter, one in which every one of these people had compelling lives before and after.”

It was in Vienna that he found money for Centropa, partly from the Culture Ministry and partly from Hannah M. Lessing, managing director of Austria’s Holocaust restitution agency.

“We immediately took to each other — we knew what we wanted to do for the survivors,” Ms. Lessing said. “As one survivor said, and this links me to Ed, ‘Everyone always asked how we died. No one asks us how we lived.’”

Philipp G. Kornreich, 93, has lived one of those extraordinary lives. Born in Vienna, he fled with his parents to Riga in 1938. When the Nazis came there, the family was sent by the Soviets to a poor collective farm in the semidesert in Kazakhstan. It was only in 1947 that he was allowed to return to Vienna, after eight weeks on trains, before ultimately becoming a professor of electrical engineering at Syracuse University.

Now living back in Vienna — “two blocks from where I started,” he said — he comes to Café Centropa to participate in “this nice Jewish community, which is now very small.”

Rita Dauber was also there. Her parents were born in Poland, in Czernowitz, now Chernivtsi in Ukraine, and survived the war. “Until the end of their lives, they always refused to speak about it,” she said. “For most of these people, their lives are a book. And Ed helped them to tell it.”

Later that evening, Mr. Serotta headed to Odesa, where he would run a workshop for Ukrainian teachers on how to use Centropa’s educational materials in a country at war. He then went to Bohdanivka, in eastern Ukraine, where in 1941-42, Romanian troops, after taking Odesa, killed up to 54,000 Jews.

This would be his 12th trip to Ukraine since Russia’s full-scale invasion in February 2022. He is working on a book about the vanished lives of famous Jewish writers and where they lived — authors like Isaac Babel, Joseph Roth, Vasily Grossman, Bruno Schulz and Paul Celan — building on articles in Tablet magazine.

Mr. Serotta, with curly gray hair, a badly repaired retina and a bit of a limp, allows that he may be getting slightly long in the tooth for such an unrelenting schedule. “The whole idea of a 76-year-old, half-blind gay man with a bad leg traveling around a war zone looking for cities where Jewish writers lived seems a bit crazy,” he conceded.

He was born into a small Jewish community in Savannah, Ga. where his father ran a credit jewelry store — “$5 down and $5 a week,” Mr. Serotta said. There were no books in the house, but his father, George, would take his son every weekend to watch the ships that came into the port. His father would call up to sailors, asking if he could bring his son aboard to take a tour.

Once, Mr. Serotta remembered, there was an Israeli ship, the Shalom, and his father brought one of the sailors home to a Sabbath dinner. It all created a wanderlust in him, he said, “just the fantasy of travel.”

After a move to Tennessee and unhappily studying marketing at the University of Tennessee, Mr. Serotta moved to Los Angeles, worked on the margins of the music industry and developed an abiding interest in photography.

He got married for four years, then divorced and later came out as gay. He moved to Atlanta in 1980, sold office supplies and was miserable, taking solace in European writers from behind the Iron Curtain whom Philip Roth had championed. So he took off to Prague, Vienna and Budapest, selling freelance articles about the failed anti-Communist uprisings and an Austria unrepentant about the Nazis.

By 1986 he found himself in Budapest, then Yugoslavia and Romania. There was enough of a market for his freelance work to keep him going, and “then I started photographing Jews,” he said, earning him a 300-page file from the Romanian secret police, the Securitate, who suspected he was a Western agent, stirring up trouble in what had been a fiercely antisemitic nation.

In early 1988, he sold everything he owned in Atlanta, except his books, and never returned to America. He moved to Budapest, where he started the work that led to Centropa, publishing a first book of photographs of Jewish life, “Out of the Shadows,” then to Prague, Berlin and finally Vienna.

He also covered the fall of the Berlin Wall in 1989, then reported on the Bosnian Serb siege of Sarajevo in the early 1990s. But it was the tales of vanished and vanishing Jewish life that captivated Mr. Serotta, and no one was documenting it, he said. “In every one of these countries, there were fascinating stories of rediscovery and self-discovery, and I got to be there to document them,” he said.

The Centropa archive has now been acquired by the U.S. Holocaust Memorial Museum as part of its permanent collection.

“It’s an incredible resource that helps fill out our understanding of Central and Eastern Europe,” said Zachary Paul Levine, director of curatorial affairs at the museum.

As a graduate student, Mr. Levine said, “I often turned to Centropa and found testimonies that helped me understand what life was like on the ground.” The way that “Ed has mixed personal documents and testimonies with photos and context made it very rewarding to me.”

Back at the community center in Vienna, Tanja Eckstein described how she ended up working for Centropa. Her father, born in 1905, was Jewish and survived Dachau after his parents were murdered, but “he wouldn’t tell me anything,” she said. “He was very traumatized and refused to come to Vienna,” making a solitary life in East Berlin.

“I was interested in Jewish history because I had no family,” she said. In Vienna’s small Jewish community, she heard about Mr. Serotta and his quixotic interest in those who survived the Holocaust and their memories of their lives and villages.

“I told my story to him,” she said. “And he gave me a big microphone and a cassette recorder and said, ‘Go for it.’”

Ms. Eckstein conducted 71 interviews in the region. “You get close to these people,” she said. When they asked when they would see her again,“Ed said, ‘Let’s get everyone together, all the interviewees.’” The first meeting in 2006 was attended by the American, British and Israeli ambassadors. “Then Ed said, ‘Let’s do it every month.’”

So was born Café Centropa, attended this evening by Kitty Schrott, 90, a Holocaust survivor and now a widow. “It’s wonderful to meet friends, to meet Jews,” she said, “and not stay at home and get sad.”