In chapter five of The Boy in the Striped Pajamas by John Boyne, Bruno and his mother and sister have finally arrived at their new home (Bruno's father arrived earlier), and Bruno has seen a strange sight outside his window. He sees people who are all wearing the same thing (uniforms) inside a fenced-in area with a lot of huts. What he sees does not make sense to him, and that is probably quite accurate for a naive nine-year-old. We have the advantage of hindsight and now know about so many of the horrible things that happened in concentration camps; most people in the world would not have been aware that such a place existed--or if they heard something of it, would not have believed it. No one wants to tell Bruno the unvarnished truth about Auschwitz, so Bruno's not knowing is realistic.
After he does not get a satisfactory answer from his sister, Bruno decides he has to be brave and ask his father about the place next door. Their conversation does not begin well, as Bruno's father makes the mistake of asking Bruno how he likes his new home. Bruno does not like it at all and thinks perhaps his father must have done something very bad at work to get them sent here, but Bruno's father reminds him that children must do what their parents say because their parents know best.
Finally Bruno gets around to asking about the people who live in the camp next door. Bruno's father answers:
"Those people...well, they're not people at all, Bruno,...at least not as we understand the term."
He goes on to tell his son that he has absolutely nothing in common with those people. He expects Bruno to adjust to his new home, and the more quickly he does that the better off all of them will be.
Bruno is not satisfied with this conversation, but he he answers his father obediently and leaves the office.