In Chapter Three of Night, Eliezer and his family arrive at Birkenau, where the "selections" begin and families are separated. Eliezer learns from another prisoner that the Nazis have brought the Jewish people to Auschwitz in order to kill them; those who are not burned by the crematoria will be forced to perform hard labor in the prison camps. Eliezer and his father nearly escape the burning pits and are sent to the barracks; however, he is separated from his mother and sister, and we later discover that both died in the concentration camps.
Once admitted to the barracks, the Jews are stripped naked, shaved, "disinfected," and then issued a uniform. In order to identify them within the camp—and to further dehumanize them—they are tattooed with a number on their left arm. Eliezer's identification number is "A-7713," which essentially ends up becoming his "name."