Brief Description: The collection relates primarily to Friedman's post-war research on the history of the Holocaust as well as to his administrative activities in various organizations. The bulk of the collection consists of second-hand sources collected by Friedman. Correspondents include: H. G. Adler, Hannah Arendt, Rachel Auerbach, Salo Baron, Ben Zion Dinur, Nathan Menachem Gelber, Rudolf Glanz, Jacob Glatstein, Israel Halpern, Arthur Herzberg, Raul Hilberg, Joseph Kermish, Israel Klausner, A. M. Klein, Leibush Lehrer, H. Leivick, Jacob Lestschinsky, Raphael Mahler, Nahum Baruch Minkoff, Shmuel Niger, Joseph Opatoshu, Koppel Pinson, Leon Poliakov, Gerald Reitlinger, A.A. Roback, Isaac Schwarzbart, Hillel Seidman, Genia Silkes, Anna Simaite, Isaac Nachman Steinberg, Michael Weichert, Mark Wischnitzer. Materials on the Holocaust are primarily arranged by ghetto or concentration camp. Included are: eyewitness accounts collected by the Central Jewish Historical Commission in Poland; depositions relating to the trial of Michael Weichert; materials on Nazi war criminals. Papers relating to Friedman's organizational activities include: records of the Historian's Circle of the YIVO Institute; records of the YIVO-Yad Vashem joint projects; records of the Central Jewish Historical Commission in Poland. The collection also includes Friedman's personal papers and a bibliography of his writings.