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" (mentioning the Jedwabne pogrom); however, due to censorship in the Polish People's Republic he could not write on killing of Jews by Poles. 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"