Ph. D., Professor at the Hebrew University, Jerusalem, 1971-1993. Director of the Research Center of Yad Vashem, 1975-1983. Head of the Institute of Contemporary Jewry, Hebrew University, 1983-1985. Chief Historian of Yad Vashem, Chairman of the Research Steering Committee of Yad Vashem, Member of Yad Vashem Executive. Member of the Scientific Committee, US Holocaust Memorial Museum, Washington.

Publications include: Author and editor of many books on the Holocaust. The Jews of Warsaw: Ghetto-Underground-Uprising (1982), Resistance: The Warsaw Ghetto Uprising (1998), ed., Encyclopedia of the Holocaust (1989).