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

He looked the boy up and down as if he had never seen a child before and wasn't quite sure what he was supposed to do with one: eat it, ignore it or kick it down the stairs.

I am frustrated by celebrities who decide to write children's books because they think it's easy. That drives me crazy. It's frustrating because it's unfair to children. Because they'll get a lot of attention, they'll get a lot of marketing budget and so on just because they're a celebrity - the Madonnas, the Ricky Gervaises, the Russell Brands.

With the adult ones, I feel I need to get as deep inside the psychology of a character as I can, and that needs to be first-person. In the children's books, I feel I need some distance. I don't want to be the nine-year-old at the center of the story. I need to have some type of narrative voice.

I think that books for young people should have serious and important themes, they shouldn't be trivial. So the books I write, they would be the kind of stories you would write in an adult novel only they just happen to feature a child at the center of them.

I was a very quiet child, quite introverted, really. Independent, yes; I didn't need a lot of supervision. Less so than I did when I got older, maybe. But I was a bookish child, not surprisingly. I could sit quite happily in a corner for hours and entertain myself with books.

I like reading books about kids where there weren't really many adults, where they didn't need an adult to come and solve the problems for them. They could use their own ingenuity, use their own talents to solve whatever the issue was. And I like that still. I think that children want to read about heroic children. They don't want to read about children that have to be saved all the time.

I like the idea of standalone novels. I always found with series of books, it's something that publishers love obviously because they can make a lot of money and they build an audience from book to book, but I don't like that as a writer. I prefer the idea of just telling a story, completing it within your book, and moving on and not forcing a child to read eight of them.