In 1940, the historian Emanuel Ringelblum established a clandestine organization, code named Oyneg Shabes, in Nazi-occupied Warsaw to study and document all facets of Jewish life in wartime Poland and to compile an archive that would preserve this history for posterity. As the Final Solution unfolded, although decimated by murders and deportations, the group persevered in its work until the spring of 1943. Of its more than 60 members, only three survived....