Nechama Tec, a Polish Jew who pretended to be Roman Catholic to survive the Holocaust and then became a Holocaust scholar, writing about Jews as heroic resisters and why certain people, even antisemites, became rescuers, died on Aug. 3 at her home in Manhattan. She was 92.

Her death was confirmed by her son, Roland.

In “Defiance: The Bielski Partisans” (1993), Dr. Tec’s best-known book, she described the courageous actions of Tuvia Bielski, who commanded a resistance group that fought the Germans and, more important, saved some 1,200 Jews. The partisans entered ghettos under siege and brought Jews back to the Belarusian forest, where Mr. Bielski had built a community for them.

“Defiance” gave Dr. Tec a platform to show that Jews saved other Jews during the war and were more active in resisting the Nazis than some have commonly believed.

When a friend suggested to the filmmaker Edward Zwick that “Defiance” would make a good movie, he was not immediately persuaded.