The process of moving Jews from smaller areas into a bigger one is called concentrating. This makes it easier for a large number of Jews to be rounded up all at once to be deported to an extermination or work camp. The men of Reserve Police Battalion 101 might not totally understand what will ultimately happen to the Jews they are concentrating; remember, the use of gas chambers in this area only began a few months before and the men themselves think they’re in Poland to provide traditional police services, such as guard duty or helping enforce rules.