LOS ANGELES -- Rudolf Vrba, one of a handful of prisoners to escape from Auschwitz during World War II and the coauthor of the first eyewitness report detailing the extent of the atrocities there, died of cancer March 27 at a hospital in Vancouver. He was 81.
Mr. Vrba was credited with saving the lives of more than 100,000 Jews, most of them Hungarians.
Part of the Sonderkommando, the special unit assigned to dispose of the bodies of those killed in the mass extermination, Mr. Vrba had firsthand knowledge of the brutality at Auschwitz, where 1.5 million people were killed.
''Vrba's experience as a Sonderkommando was key to the report having the authority that it did," said Bernie M. Farber, chief executive of the Canadian Jewish Congress. ''Rudy had a picture-perfect mind, and he remembered the languages that [the prisoners] spoke, and he knew how many could be crammed into a railroad car."
Mr. Vrba, who co-wrote the report with fellow prisoner Alfred Wetzler, said he escaped from the camp in Poland to save lives.
''The strength of the Final Solution was its secrecy," Vrba told the Ottawa Citizen last year. ''I escaped to break that belief that it was not possible. And to stop more killings."
Mr. Vrba was born Walter Rosenberg in Topolcany, Czechoslovakia. He was working as a laborer in March 1942 when he was taken into custody for being Jewish. Two months later, Mr. Vrba, then 18, was deported and -- after a stop in another concentration camp -- reached Auschwitz on June 30, 1942.
By midsummer he had been assigned to a work a detail sorting possessions confiscated from prisoners. In June 1943 he was given the job of registrar in the quarantine section of the death camp. His last detail at Auschwitz was a ''Sonderkommando."
Mr. Vrba's photographic memory enabled him to retain much of the geography and the placement of the facilities as he went about his work. He also reportedly heard guards talking about the impending arrival of a new shipment of inmates, what they termed ''Hungarian sausage." He took this conversation to mean Hungarian Jews, the last Jewish population in Europe to be deported.
In April 1944, with the help of the camp underground, Mr. Vrba and Wetzler planned their escape. The two men hid in a woodpile just outside the camp's barbed-wire inner perimeter.
They knew the guards generally searched for missing prisoners for three days before giving up. After the third day, the two men made their way into the countryside using a page from a children's atlas as a guide. Eight days later they crossed the border into Slovakia and found members of the underground who would help them.
Working with local Jewish leaders, the two men prepared a 32-page report that offered a precise description of the geography of Auschwitz, including diagrams locating the gas chambers and crematories at the area of the camp known as Birkenau. The report also detailed how the selection of prisoners -- who would live and who would be assigned to work details -- was carried out. By late April 1944, the report was on its way to members of the Jewish underground in Hungary. A copy of the report was sent to the Vatican in late May, and by mid-June officials of the US and British governments had copies as well.
On May 27, 1944, two other prisoners escaped Auschwitz and arrived in Slovakia in early June. They said that, despite the warnings in the Verba-Wetzler report, tens of thousands of Hungarian Jews had begun arriving at Auschwitz in mid-May and were put to death. Their account of what had transpired at the camp was combined with the Vrba-Wetzler findings to create what became known as the Auschwitz Protocol.
Bowing to world pressure generated by the eyewitness accounts and perhaps fearful of postwar retribution, Hungarian officials stopped the deportation of Jews in July 1944.
Mr. Vrba became a member of the Slovak partisans and fought until the end of the war. He took the name Rudolf Vrba during his time fighting the Nazis.
After the war, he studied chemistry in Prague and had earned his doctorate by 1951. As a researcher, his specialty was the chemistry of the brain. He also did work on diabetes and cancer. He lived in Israel and then England before immigrating to Canada in the 1970s, where he became a professor of pharmacology at the University of British Columbia.
Wetzler died in Slovakia in 1988.
Mr. Vrba leaves his wife, Robin; a daughter; and two grandchildren.
He wrote a book of personal recollections, ''I Cannot Forgive," published in 1964, and contributed to four documentary films, including ''Shoah."
To the end, however, Mr. Vrba believed his report did not save enough lives and was critical of Jewish officials in Hungary for not giving it wider distribution.