Leah grew up in Praga, a suburb of Warsaw, Poland. She was active in the Ha-Shomer ha-Tsa'ir Zionist youth movement. Germany invaded Poland in September 1939. Jews were forced to live in the Warsaw ghetto, which the Germans sealed off in November 1940. In the ghetto, Leah lived with a group of Ha-Shomer ha-Tsa'ir members. In September 1941, she and other members of the youth group escaped from the ghetto to a Ha-Shomer ha-Tsa'ir farm in Zarki, near Czestochowa, Poland. In May 1942, Leah became a courier for the underground, using false Polish papers and traveling between the Krakow ghetto and the nearby Plaszow camp. As conditions worsened, she escaped to Tarnow, but soon decided to return to Krakow. Leah also posed as a non-Jewish Pole in Czestochowa and Warsaw, and was a courier for the Jewish National Committee and the Jewish Fighting Organization (ZOB). She fought with a Jewish unit in the Armia Ludowa (People's Army) during the Warsaw Polish uprising in 1944. Leah was liberated by Soviet forces. After the war she helped people emigrate from Poland, then moved to Israel herself before settling in the United States.
Soon we started to organize ourselves and I was assigned, we were, we did, I mean, again our commanding people, I mean the people at the top of the group, like Yitzhak Zuckerman and others--I mention his name more often than others because almost all the leading people of Ha-Shomer ha-Tsa'ir died in the war, except maybe for Haika Grosman. And, well, we started to organize not only to, to have a gathering point for Jews to come to, but also to send out people to look for liberated Jews, you know. Because when people were liberated by the Soviet army, the first impulse of people was going back to their places. That was the natural instinct, to see if somebody survived, if the house survived, if something can be rescued. So I was assigned to, to do that with another girl. Her name was Krysia Biderman. Actually her real name was Sara Biderman, Krysia was her pseudonym during the war. And we were traveling criss-cross Poland looking for surviving Jews, and we found them. And sometimes these meetings were so packed with emotion that I, I lack the words to describe it, you know. Because the idea that we are really survivors couldn't sink in yet. You were full of apprehensions that maybe it will change again, you know. For, for, for years you were, lived like a hunted animal. It, it gets into your psyche. It's very difficult to get rid of that feeling that you are not in danger anymore. All these self-defense mechanisms are still with you, you know, and in many cases people were reluctant to admit that they are Jews. In many places, places they didn't want to talk to us. They didn't know who we are. But there were also cases when we came and we got such a warm welcome. I remember, I don't even remember which place, what was the name of the place, but we came to a small place and there was a Jewish family there and we got a very warm welcome. We were tired, you know, traveling constantly on the ways and, and she gave us a good supper and she put us into bed and we could wash and, it was real Jewish hospitality that was known before the war, which was absent during the war and again, you know, it was like slowly coming back to life.