Immanuel was born on January 1, 1915, in Vilna, to Avraham ben Shimon Katz, a fervent Zionist and Adina, daughter of Rabbi Yosef and Ethel Prujan, a private tutor. Even in his youth, his talents were obvious. He studied Hebrew, Talmud and Bible with a private tutor. At age ten, he was accepted to the Hebrew Gymnasium, then to the Epstein Gymnasium, which taught in Polish. At age twelve, he joined Beitar, setting up a cell in the Gymnasium and publishing materials for students in the spirit of the movement. He was the commander of Beitar in Vilna and was part of the Galil command staff. He made aliyah in 1934 to study mathematics at university in Jerusalem and he studied there, until his financial situation made him stop. He moved to Ramat Gan, where he worked as the secretary of the Histadrut. A bit later, he started work as an editor at the HaBoker newspaper, due to the publication of his essay, “The Racial Yearnings of Assimilationist Judaism.”
In 1940, he married Hannah, daughter of Shlomo Gelber from Warsaw, who made aliyah in 1934. They had two children and seven grandchildren.
He was an IZL member, and after the split he followed Yair to Lehi. He was active in writing articles and explaining the ideology of the underground. He was part of the editorial board of Lehi’s periodical, HeHazit. He wrote the famous essay: “The Empire Sets, Judah Rises,” which made a considerable impression both inside and outside the Land of Israel. Immanuel was arrested by the CID and kept for a long time in Latrun.
He worked on HaMivrak, the Lehi periodical founded in 1948, near the time the State was established. He was also on the editorial board of HaSullam, and he worked on Herut as well. He memorialized the story of Lehi in Lohamei HaHofesh BeIsrael. He also wrote a summary of the story in Hoveret Lohamei Herut Israel. For four years (5723-5727), he edited a number of monthly albums called Lapid, to educate HaNoar HaOved VeHaLomed with a nationalist spirit. He also worked for the Jewish newspaper, Letzte Zeitung.
He published two volumes of Plutarch’s Lives. He also edited the writings of Boccaccio and Pitigrilli, The Bible in Art, and short summaries of great writers for the youth (translating the first volume).
He passed away on December 3, 1978.