Some 62,937 documents were sent to Germany between Sept. 21, 1961 and Nov. 7, 1999 to aid in war crimes investigations, including evidence of help given to Jews by Poles during the war.
The family of a "Schindler's List" survivor gave a collection that the museum's director called "the biggest gain for decades in the history of our archive."
Having original documents, including photos and personal letters, will "allow for a better and more comprehensive understanding of the motivation of the perpetrators," according to the museum.