Simon Wiesenthal, 96, the controversial 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 had a kidney ailment.

Called the "deputy for the dead" and "avenging archangel" of the Holocaust, Wiesenthal after the war created a repository of concentration camp testimony 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 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. This was later considered by many a remarkable achievement, coming during the Cold War when the major world powers were recruiting former Nazis to help govern countries along the Iron Curtain. There was little political will to relive World War II.

Martin Mendelsohn, a Washington lawyer who in the late 1970s helped establish the Nazi-hunting Office of Special Investigations within the U.S. Justice Department, said in an interview that Wiesenthal "kept the memory of the Holocaust alive when everyone wanted it to go away. When Jewish groups wanted it to go away, he wanted to keep it alive. That is his signal accomplishment."

Wiesenthal made many enemies, even among high-profile Jews who criticized his methods and said he was out to glorify himself. He 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.

Following the principle "justice, not vengeance," Wiesenthal said trials of Nazis would provide moral restitution for the Jews and offer 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."

His targets included Adolf 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 select women and children at a camp in Poland who were sent to the gas chamber and later was found living as a housewife in Queens, N.Y.

Dogged Pursuit

Through informants, who included veterans of rival Nazi-era intelligence services, Wiesenthal helped expose such organizations as Odessa, which slipped former Nazis into 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," a bureaucrat whose policies condemned to torture or death tens of thousands of people at a time.

In 1947, Eichmann's wife sought to have the Nazi official declared dead. Wiesenthal was able to prove that the alleged witness to the death was Eichmann's brother-in-law, preventing the death certificate from being approved.

Wiesenthal, who knew many SS men who remarried their own "widows," said his greatest contribution was "destroying the legend" that Eichmann had died.

By keeping the file active, he helped launch an international manhunt that resulted in Eichmann's capture by Israeli intelligence. In 1960, Mossad agents kidnapped Eichmann from a street in Buenos Aires. He stood trial in Israel and was hanged in 1962.

An early book by Wiesenthal, "I Hunted Eichmann" (1961), had a more-boastful title than the content inside suggested but made its author an overnight sensation after years of toiling in obscurity, according to biographer Hella Pick.

Because of Mossad secrecy over the kidnapping, Wiesenthal's role appeared magnified, and he took advantage of the publicity to press his cause. This led to later denunciations of Wiesenthal by a former Mossad leader, but the Nazi hunter was unapologetic.

"Through the publicity we got information, and through the publicity we got money," Wiesenthal once said, noting that the money was essential sometimes to persuading aging Nazis to talk.

He said a former Gestapo officer once 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 once 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 being sentenced to life in prison.

Wiesenthal used such stories to convince the press that Cold War tensions did not erase the obligation to the past. He embraced romanticized, sometimes fictionalized depictions of his work, as was the case in Frederick Forsyth's novel "The Odessa File" (1972).

He never doubted his motivation for working so long against the seemingly impossible odds of righting a genocide. In a New York Times article from 1964, he described attending Sabbath services with a fellow camp survivor who had become a wealthy jeweler. The man asked why Wiesenthal had not resumed architecture, his prewar 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.' "

A Way of Life Severed

Szymon Wiesenthal was born Dec. 31, 1908, in the Eastern Galician town of Buczacz, part of what is now 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 across the street to a neighbor's house to borrow yeast one day, 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, who figured its content was successful.

(Decades later, he earned money by ghostwriting Polish political joke books at the expense of the communist regime.)

After college, Wiesenthal formed a small architectural practice in 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. Soviet leader Joseph Stalin let loose his security apparatus on Ukraine. Forced from his livelihood, Wiesenthal worked as a mechanic in a bedspring factory and unsuccessfully tried to bribe security officials so they would not take 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!"

"What I saw for the first time was systematic extermination that had no motive except to kill every Jew, starting with the ones who looked the most dangerous to Hitler. And done by people who took real pleasure in killing us," he told his biographer Alan Levy.

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 grew to think survival was unlikely and twice attempted suicide instead of facing torture. 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.

Their 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 99 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 a U.S. 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."

Taking On a Mission

Wiesenthal chose to remain in Austria because he held many of its citizens culpable for the deaths of millions of Jews. He worked with a Jewish relief agency to clear names of suspected Nazis and demanded that Jews who had collaborated with Nazis have no place in postwar Jewish organizations.

In 1947, he started his independent Jewish Documentation Center in Lidz. (It later moved to Vienna.) He had grown disenchanted with working for the Allies and bristled at following orders. "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.

Wiesenthal often spoke of the necessity of his work by citing the Anne Frank case and his search for the man who arrested her family. He started the hunt after meeting a postwar generation of Austrians who labeled the horror stories of death camps "Jewish propaganda" and viewed "The Diary of Anne Frank" as a hoax.

Through contacts at investigation agencies and resources such as the telephone directory of the Gestapo in Holland, he found Frank's arresting officer, Silberbauer, working as an inspector for the Vienna police. When the man was suspended in 1963, Wiesenthal made sure it received great attention by phoning the Dutch press.

The case went nowhere when prosecutors said that 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 mounting a rigorous press offensive in other cases.

He did just that in the 1960s and 1970s during his successful campaign to prevent the expiration of German statutes of limitation against Nazi war criminals. He enlisted the help of Sen. Robert F. Kennedy (D-N.Y.), one of his chief American admirers.

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

The Cost of Controversy

In 1968, Wiesenthal called a news conference to highlight the large number of former Nazis serving as ranking officials in the communist East German government. The East Germans countered with accusations -- which biographer Pick wrote were false -- that Wiesenthal was on the Mossad and Central Intelligence Agency payroll. They also claimed he was a Nazi collaborator in wartime.

The collaboration charge was repeated by Bruno Kreisky, the Socialist chancellor of Austria, whom Wiesenthal often singled out for the ex-Nazis serving in his Cabinet. They traded slurs over many decades and, in the end, Wiesenthal won a slander suit against Kreisky.

Neither Wiesenthal nor the World Jewish Congress gained anything during the ugly public relations battle over the disputed war record of Austrian statesman Kurt Waldheim. Waldheim, the former United Nations secretary-general running for the presidency of Austria in the early 1980s, had served in the German army during World War II.

The World Jewish Congress accused Waldheim of participating in Nazi atrocities. Wiesenthal's brief investigation turned up nothing, though he called Waldheim a "world-class liar." Wiesenthal said he lacked evidence to prove Waldheim was culpable for mass killings or deportations.

The WJC launched a massive campaign to discredit Wiesenthal. Eli M. Rosenbaum, a U.S. Justice Department Nazi hunter and former WJC general counsel, wrote a book called "Betrayal" (1993) that criticized Wiesenthal for his alleged coverup of Waldheim's wartime activities as Waldheim went on to win the presidency.

Although the accusations against him stung, Wiesenthal found his reputation greatly enhanced in his adopted country of Austria, which had long viewed him as a meddler, according to Pick.

To many, his name was long a symbol of human conscience. Wiesenthal's honors included the U.S. Congressional Gold Medal (1980), the Presidential Medal of Freedom (2000) and an honorary British knighthood (2004).

In 1977, Rabbi Marvin Hier named his Los Angeles-based Jewish human rights center after Wiesenthal. Wiesenthal remained officially unaffiliated with the California center, but Hier agreed to send him a modest monthly stipend as Wiesenthal kept his office in Austria open, mostly hoping to outlive the surviving handful of Nazi war criminals.

Wiesenthal wrote prolifically to provide some income for his work. Besides his memoirs, his books included "The Sunflower" (1969), part memoir, part parable of forgiveness; and "Sails of Hope" (1973), in which he studied the possibility that Christopher Columbus was Jewish. He joked that American Jews might celebrate three holy events: Rosh Hashanah, Yom Kippur and Columbus Day.

Wiesenthal was described as a man who accepted material sacrifice -- he lived sparsely -- but craved name recognition. Some felt this desire for attention diminished him, among them Holocaust memoirist Elie Wiesel, who found Wiesenthal boorish and covetous of Wiesel's Nobel Prize.

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."

Survivors include a daughter, Pauline, of Herzliya, Israel; three grandchildren; and seven great-grandchildren.

"If all of us forgot, the same thing might happen again, in 20 or 50 or 100 years," Simon Wiensenthal said.Simon Wiesenthal attends a trial of suspected Nazi war criminals in Vienna, Austria, in 1958. He said he helped bring 1,100 ex-Nazis to trial.