 From 1954–56 he was director of research at the War Documentation Project in Washington and Virginia, analyzing captured German documents from the war.Stemming in part from his interviews during the Harvard Project, in 1957 Dallin published "German Rule in Russia, 1941-1945", which became the classic, definitive account of the German occupation of parts of Russia during World War II.It won the George Louis Beer Prize for European international history since 1895.