Born in Karelitz, Belarus, Yitshok’s father was a Hebrew writer and the director of a Hebrew school. Katsenelson traveled to Switzerland in 1910, opened a private Hebrew school in Lodz and remained its director until WWII. He visited America in 1921 and Palestine (Israel) in 1925 and 1935. When the Nazis occupied Lodz in 1939, he went to Cracow and then settled in Warsaw where he was active in the Socialist-Zionist underground youth organization “DROR” and contributed to the underground press. His wife, Yudit, a teacher of Polish in Jewish schools was killed with two of their three sons in the Warsaw Ghetto. Since he had a visa from Honduras, he and his remaining son were sent to France to the French concentration camp “Vittel”. From there he and his son were taken to Auschwitz in April 1944. He was a productive writer in Hebrew and in the Warsaw Ghetto he wrote in Yiddish, Der Tog fun Mayn Groisn Umglik, (“The Day of my Great Misfortune”), Vey Tsu Dir, (“Woe Unto You”), Dos Lid Fun Shlomo Zhelikovski, (“The Song of Shlomo Zhelikovski”), Lider Fun Derhargetn Yiddish Folk, (“The Song of the Murdered Jewish People.”) and Lider fun Hunger, Lider fun Kelt, (“Songs of Hunger, Songs of Cold”). He wrote the play Iyuv, (“Job”) in verse while in the Warsaw Ghetto. (See his poem Aynladung Tsu an Ovnt fun Tanakh, (“Invitation to an Evening of Tanakh”), written in the Warsaw Ghetto, (see in the appendix of this book). Prior to the Warsaw Ghetto was writing in Hebrew. But in the Ghetto he wrote in Yiddish.