You’re my best friend, Shmuel,’ he said. ‘My best friend for life.

But still there are moments when a brother and sister can lay down their instruments of torture for a moment and speak as civilized human beings and Bruno decided to make this one of those moments.

The thing about exploring is that you have to know whether the thing you've found is worth finding. Some things are just sitting there, minding their own business, waiting to be discovered. Like America. And other things are probably better off left alone. Like a dead mouse at the back of the cupboard.

War today is such a more visible thing. We see it on television, on CNN. In 1914, war was a concept.

What exactly was the difference? he wondered to himself. And who decided which people wore the striped pajamas and which people wore the uniforms?

I started reading Dickens when I was about 12, and I particularly liked all of the orphan books. I always liked books about young people who are left on their own with the world, and the four children's books I've written feature that very thing: children that are abandoned by their families or running away from their families or ignored by their families and having to grow up quicker than they should, like David Copperfield - having to be the hero of their own story.

Do you see the irony at all, Tristan?’ I stare at him and shake my head. He seems determined not to speak again until I do. ‘What irony?’ I ask eventually, the words tumbling out in a hurried heap. ‘That I am to be shot as a coward while you get to live as one.