Martha Nierenberg had barely turned 20 when she was bundled off a train in central Hungary and hidden by nuns in a Roman Catholic hospital. It was March 1944, and a Nazi occupying force that included Adolf Eichmann would immediately embark on the annihilation of 500,000 Hungarian Jews.

Mrs. Nierenberg, who was born into one of Hungary’s wealthiest families, evaded capture for two months before friends assured her she could venture home. There she learned that she would be among 42 family members and close associates who were to be driven by the Germans to the Austrian border and, several weeks later, allowed to escape to Switzerland or Portugal. The cost was high. The Nazis strong-armed the family into signing away their estates, including some 2,500 pieces of precious art.

A trained biochemist who spoke six languages, Mrs. Nierenberg made it to the U.S. with her mother in 1945. She set off on a career as a scientist and researcher at M.I.T. and the Rockefeller Institute for Medical Research in New York, and then as an entrepreneur when, in 1954, she and her husband founded the Dansk Designs housewares company.

Mrs. Nierenberg died in her sleep on June 27 at a senior living facility in Rye, NY. She was 96. At her death, she was a lead plaintiff in a 30-year Holocaust art restitution battle with Hungary that counts as one of the highest-value cases ever pursued by a single family. Among the 40 paintings Hungary has refused to return are four by El Greco and others by Corot, Velazquez and Courbet. Her granddaughter, Robin Bunevich, estimates that the collection is worth $100 million. She said the family would continue to press the case.