Have you ever heard the phrase the eyes are the window to the soul? Well, in The Boy in the Striped Pajamas, we can flip this around: In this book, the window is an eye of Bruno's soul. Yes, that feels a little awkward to say, but hang with us.
After moving to Auschwitz with his family, Bruno has no clue that his new neighbor is one of the biggest, baddest concentration camps in the entire Holocaust. He's only nine-years-old, after all, and it's not like anyone in his family would ever tell him (for more on this, read up on Bruno's parents in the "Characters" section). Plus, he's way more concerned about having left his friends and fancier house behind—you know, kid concerns.
In Bruno's room, however, there's a window. Check out what happens when he finds it:
He put his face to the glass and saw what was out there […] his hands stayed by his sides because something made him feel very cold and unsafe. (2.95)
Through the glass window, Bruno sees the prisoners and buildings of Auschwitz—and the more he looks, the more he wants to understand what they're doing and who they are. The window, then, represents a loss of innocence for our main man (er, boy). As he looks through it and his comprehension grows, we understand that something is shifting deep inside him—what he sees makes "him feel very cold and unsafe." And importantly, he doesn't just pull down the blinds or look away.
After seeing the prisoners through his window, Bruno starts to question what's going on. He gets his sister, Gretel's, input, and while she's not exactly a reliable source of information, as her attention is easily drawn back toward her dolls, an important distinction between the siblings emerges: Bruno stays curious. The more he asks, the more he knows, and although he never understands everything, after looking through the window the first time, Bruno is no longer content to live in ignorance, either.