Simon Wiesenthal, the Nazi hunter who pursued hundreds of war criminals after World War II and was central to preserving the memory of the Holocaust for more than half a century, died yesterday at his home in Vienna, Austria. He was 96.

After the war, Wiesenthal created a repository of concentration camp testimonials and dossiers on Nazis at his Jewish Documentation Center. The information was used to help lawyers prosecute those responsible for some of the 20th century’s most abominable crimes.

Wiesenthal spoke of the horrors firsthand, having spent the war hovering near death in a series of labor and extermination camps. Nearly 90 members of his family perished.

After the Nuremberg Trials of the late 1940s, Wiesenthal remained a persistent and lonely voice calling for war crimes trials of former Nazis. He virtually single-handedly kept the issue alive until it was taken up by others, notably with the execution of Adolf Eichmann in 1962.

Following the principle “justice, not vengeance,” Wiesenthal said trials of Nazis would provide moral restitution for the Jews and have the best chance of preventing the anti-Semitism that defined the first half of his life.

“I’m doing this because I have to do it,” he once said. “I am not motivated by a sense of revenge. Perhaps I was for a short time in the very beginning … Even before I had had time to really think things through, I realized we must not forget. If all of us forgot, the same thing might happen again, in 20 or 50 or 100 years.”

However, Wiesenthal made many enemies, among them high-profile Jews who criticized his methods and self-publicizing. Wiesenthal justified his active use of the press and eagerness for public recognition by pointing to the sizable battle he waged independent of any government or large organization.

His targets included Eichmann, one of the foremost planners of Jewish extermination; Fritz Stangl, commandant of two death camps; Gestapo officer Karl Silberbauer, who arrested Anne Frank in her Amsterdam hideout; and Hermine Braunsteiner Ryan, who helped process the murder of women and children at a camp in Poland and later was found living as a housewife in Queens.

Through informants, which included veterans of rival Nazi-era intelligence services, Wiesenthal helped expose organizations like Odessa, which slipped former Nazis to South America. In various ways, including procuring prosecution witnesses, Wiesenthal said he helped bring 1,100 ex-Nazis to trial.

His most celebrated early case concerned Eichmann, who had vanished after the war. He said Eichmann was the essence of the “desk murderer,” the bureaucrat whose policies condemned to torture or death tens of thousands of people at a time.

In 1947, Wiesenthal was able to block Eichmann’s wife from having Eichmann declared legally dead. Wiesenthal later noted that he knew of many SS men who remarried their own “widows.” By keeping Eichmann’s file active, Wiesenthal helped launch an international manhunt that culminated in Eichmann’s capture. In 1960, agents from Israel’s Mossad kidnapped Eichmann from a street in Buenos Aires. He stood trial in Israel and was hanged.

An early book by Wiesenthal, “I Hunted Eichmann” (1961), made it sound as if his role in the capture was perhaps greater than it was, and made its author an overnight sensation after years of toiling in obscurity. Wiesenthal took advantage of the publicity to press his cause.

When Mossad leaders later broke their customary secrecy to charge him with exaggeration, the Nazi hunter was unapologetic.

“Through the publicity we got information, and through the publicity we got money,” Wiesenthal once said, noting that money was essential to persuading aging Nazis to talk. He said a former Gestapo officer demanded $25,000 for information leading to the capture of Stangl. Wiesenthal uneasily settled on $7,000, which he said amounted to perhaps a penny for every person killed at Treblinka, one of Stangl’s camps.

“I had three possibilities,” Wiesenthal wrote. “To throw the man out, to strangle him, or to deal with him. I chose the third option, because I felt that the arrest of a mass murderer justified such a payment.”

Captured in Brazil, Stangl was taken to Germany in 1967. He died in jail in 1971 after receiving a life sentence.

Such stories helped convince the press that Cold War tensions did not erase the obligation to the past. But Wiesenthal was sometimes criticized for embracing more romantic, sometimes fictionalized depictions of his work, as was the case in Frederick Forsyth’s novel “The Odessa File” (1972).

He once wrote of attending Sabbath services with a fellow camp survivor who had become wealthy jeweler. The man asked why Wiesenthal had not resumed architecture, his pre-war trade, for it would have made him rich.

“You’re a religious man,” Wiesenthal told his friend. “You believe in God and life after death. I also believe. When we come to the other world and meet the millions of Jews who died in the camps and they ask us, ‘What have you done?’ there will be many answers.You will say, ‘I became a jeweler.’ Another will say, ‘I smuggled coffee and American cigarettes.’ Another will say, ‘I built houses.’ But I will say, ‘I didn’t forget you.'”

Szymon Wiesenthal was born December 31, 1908, in the Galician town of Buczacz, part of what is now the western Ukraine. His father, a sugar wholesaler, died while fighting in World War I, and the family struggled amid competing Ukrainian, Russian, and Polish forces.

It was common to find drunken soldiers raping and killing Galicians, especially Jews. When his mother sent him one day across the street to a neighbor’s house to borrow yeast, a saber-wielding Cossack slashed Wiesenthal’s right thigh. The scar remained for the rest of his life.

An interest in drawing, combined with knowledge of home-building from his stepfather’s brick factory, led him to study architecture at the Czech Technical University in Prague. He also edited a satirical magazine that the authorities often confiscated – a matter of pride to its young editor. Decades later, he earned money by ghost-writing Polish political joke books at the expense of the communist regime.

After college, Wiesenthal practiced architecture the Ukrainian city of Lvov. In 1936, he married Cyla Mueller, his girlfriend since high school. Their few prosperous years ended with the dissolution of the Soviet-German “non-aggression” pact of 1939. Stalin let loose his security apparatus on the Ukraine. Forced from his livelihood, Wiesenthal worked as a mechanic in a bedspring factory and unsuccessfully tried to bribe security officials from taking away his family to certain death.

Wiesenthal himself was rounded up with other Jews and nearly killed by Ukrainian soldiers. Each man stood against a wall and beside a wooden crate that was meant to hold a corpse. An officer shot a man in the neck, swigged liquor, and shot the next man. As the officer approached Wiesenthal, church bells sounded. “Enough!” the officer said. “Evening mass!”

Wiesenthal and his wife were forced to work in a labor camp that serviced the German railroad. He helped Cyla, a blonde who could pass as Polish, escape through the underground, but each thought the other died during the war.

He and Cyla found each other months after the German surrender by scanning lists of survivors. She remained, until her death in 2003, Wiesenthal’s solid, if long-suffering, defender. Wiesenthal could never stop his work and once turned down her suggestion that they move to Israel and “be normal people.”

During the war, Wiesenthal was held in a succession of camps, and escaped at one point for eight months. Recaptured and facing torture, he twice attempted suicide. He said the turning point was a conversation with an SS corporal one day toward the end of the war. The man bet Wiesenthal that no one would ever believe the truth of what had occurred in the concentration camps.

The exchange, Wiesenthal later said, gave him the will to live through the war.

By May 1945, when Wiesenthal was freed by Allied soldiers at Mauthausen camp in Austria, his 6-foot-tall body weighed under 100 pounds. Gradually restored to health, he transferred to an Allied base in Lidz, Austria. He went to the war crimes office and offered his services after presenting an exhaustive list of crimes he had witnessed.

Accompanying an American Army captain on his rounds to the nearby villages, Wiesenthal was allowed to make arrests – exhilarating work, he said.

“I’ll never forget our first case,” he wrote in his memoir “The Murderers Among Us” (1967).”We drove to a small house where an SS man named Schmidt lived. He had been one of our guards, an insignificant little man who looked as anonymous as his name. I walked up to the second floor, found him and arrested him. He didn’t even try to resist. He was trembling. So was I, but for a different reason. I was weak from getting up the stairs and from the excitement.”

He deliberately chose to remain in Austria because he held many of its citizens culpable for the deaths of millions of Jews. In 1947, he started his independent Jewish Documentation Center in Lidz (later it was based in Vienna). “I considered that my self-appointed task was holy, and my determination became the more pronounced, the more I learned how Jews had been abused,” he wrote in “I Hunted Eichmann.”

When money ran out in 1954 – his chief benefactor, a Swiss Jew, had died – he closed his center and worked for a Jewish vocational training organization. Wiesenthal returned to chasing war criminals full-time after publicity from the Eichmann case.

His work on the Anne Frank case did much to silence Holocaust deniers. Through contacts at investigation agencies and resources such as the telephone directory of the Gestapo in Holland, he found Frank’s arrestor, Silberbauer, working as an inspector for the Vienna police. When the man was suspended in 1963, Wiesenthal made sure it received great attention in the Dutch press.

However, the case went nowhere when prosecutors concluded Silberbauer’s actions were not war crimes and that he was not responsible for Frank’s deportation to a concentration camp.

This was not Wiesenthal’s only unsuccessful pursuit – an Austrian jury in 1963 acquitted Franz Murer, “the butcher of Vilna,” who was reputed to have killed 80,000 Lithuanian Jews. Appalled by the verdict, Wiesenthal grew more convinced of the need for a rigorous press offensive in the future.

In the 1960s and 1970s he successfully campaigned to prevent the expiration of German statutes of limitation against Nazi war criminals. He enlisted the help of Senator Robert Kennedy, a Democrat of New York, and one of his foremost American admirers.

Wiesenthal also sought greater recognition for the sufferings of the gypsies, communists, and others under the Nazi regime, and highlighted the wartime efforts of Swedish diplomat Raoul Wallenberg, who aided Jews and disappeared mysteriously in 1945 while in the custody of the Soviet Army.

In 1968, Wiesenthal called a press conference to draw attention to large numbers of former Nazis serving as ranking officials in the communist East German government. The East Germans countered with wild accusations that Wiesenthal was on the Mossad and Central Intelligence Agency payroll, and that he was a Nazi collaborator during the war.

The collaboration charge was repeated by Bruno Kreisky, the socialist chancellor of Austria, and himself a Jew, whom Wiesenthal criticized for appointing former Nazis to his cabinet. Wiesenthal also feuded with the World Jewish Congress over Kurt Waldheim’s wartime record. Mr. Waldheim, the former United Nations secretary-general, was running for the presidency of Austria in the early 1980s, and the WJC showed that he had lied about sitting out World War II.

The WJC accused Mr. Waldheim of participating in Nazi atrocities. Wiesenthal demurred after a brief investigation, though he called Mr. Waldheim a “world-class liar” for concealing his wartime service in the German army.

The WJC labeled Wiesenthal a “sleazeball” and accused him of running a cover-up for Mr. Waldheim, as Mr. Waldheim went on to win the presidency.

Wiesenthal’s honors included the U.S. Congressional Gold Medal (1980), the Presidential Medal of Freedom (2000) and an honorary British knighthood (2004). His failure to win a Nobel Peace Prize was blamed by many on the Waldheim affair.

In 1977, Rabbi Marvin Hier named his Los Angeles-based Jewish human rights center after Wiesenthal. Wiesenthal remained officially unaffiliated with the California center, and continued to keep his office in Austria open, mostly in hopes of outliving the surviving handful of Nazi war criminals.

Besides his memoirs, Wiesenthal’s books include “The Sunflower” (1969), part-memoir, part-parable of forgiveness; and “Sails of Hope” (1973), in which he postulated that Columbus discovered the New World in a search for a new Jewish homeland. He joked that American Jews might celebrate three holy events: Rosh Hashana, Yom Kippur, and Columbus Day.

Ever image-conscious, Wiesenthal once said Paul Newman would be the ideal man to play him onscreen. When told the actor disliked portraying the living, Wiesenthal said: “Give him also my regards, but for his comfort I wish not to die.”