The boy in the striped pyjamas. John Boyne.

"It was as if it were another city entirely, the people all living and working together side by side with the house where he lived. And were they really so different? All the people in the camp wore the same clothes, those pyjamas and their striped cloth caps too; and all the people who wandered through his house (with the exception of Mother, Gretel and him) wore uniforms of varying quality and decoration and caps and helmets with bright red-and-black armbands and carried guns and always looked terribly stern, as if it was all very important really and no one should think otherwise.
What exactly was the difference? he wondered to himself. And who decided which people wore the striped pyjamas and which people wore the uniforms?."