After the war, Datner served for two years as head of the Białystok branch of the
Central Committee of Jews in Poland (
CŻKH). "A survivor himself, he deposited his own testimony at the Jewish Historical Commission in Białystok on 28 September 1946." Of
Jewish extraction, he was dismissed from his post during the
1968 Polish political crisis but was rehabilitated soon after. In 1969–70 he presided over
Warsaw's
Jewish Historical Institute, and he was one of the historians at the . According to
Bernd Wegner, Datner drew up the most comprehensive documentation of
Nazi Germany's
war crimes and atrocities in eastern Poland. In 1966 he published an article on "The Extermination of the Jewish Population in the District of Bialystok". states that Datner wrote in similar vain to authors engaging in "heroic-martyrological discourse".
Alexander B. Rossino names Datner as
the eminent historian of Wehrmacht war crimes in Poland. == Family ==