Ms. Fahidi lost 49 relatives in the Holocaust, including her mother and sister Gilike, then 11. Her last glimpse of them was on the ramp at Birkenau, where arriving Jews were sorted into those sent instantly to the gas chambers and those — like Ms. Fahidi — selected for hard labor and thus a chance at survival. She was later transferred from Auschwitz to Münchmühle, a camp near Stadtallendorf, in the German state of Hesse.

HER father also perished in the camps, whose horror she has chronicled in a memoir in this 70th year since the liberation of Auschwitz, and which she wishes to see judged, finally, when a former Auschwitz guard goes on trial in Germany in April.

“When I came home from the Holocaust,” she said, using an everyday phrase in German that seems implausible when containing so much tragedy, she ran right past the house in Debrecen, eastern Hungary, where her prosperous family had lived.

The house was so rundown, she said, that “I knew instantly I would not have anyone to look for.” The inhabitants “were complete strangers who really did not let me in my own home.”

It turned out, in late 1945, that she did have a distant aunt and uncle who had survived. For two years, she said, she was bedridden — because of a congenital condition that left her unable to sit for long periods after the camps — in their home in Nove Zamky, now part of Slovakia. Her uncle, a doctor forced by the anti-Semitic laws of post-World War I Hungary to get his medical training in Vienna and Prague, was, like her, an avid reader. He gave her Marx’s “Das Kapital,” which she read “from the first word to the last.”