Phantom' was for me an interesting technique of telling the story. You have one voice that it is in the present telling what is happening, and then there's one voice from the past that's also driving the story forward. And you know that the two story lines will meet eventually.

At nineteen I was pretty sure I was going to be a professional soccer player. At that time I played for one of the Norwegian premier leagues. But I tore ligaments in both knees, so I started studying business administration and economics and became a financial analyst, and I worked at a brokerage firm as a stockbroker.

The only pressure I feel is to write good books. And to not replicate the previous book. Whether you have a thousand readers or a million readers it doesn't change the pressure. I never feel tempted to give the reader what I think the reader wants.

I'm not a big crime reader, but I'm reading Michael Connelly's 'The Reversal.' I'm going back to his novels. I'm also reading Keith Richards' 'Life.' I'm always fascinated by the transition from the innocent late '60s and early '70s and the youth culture becoming an industry.

I think I was righteous. I saw myself as the good guy in my own movie. I didn't get into many fights when I was younger, but when I did, they were righteous. I always thought I was defending something good. I fought for friends who couldn't fight for themselves. I was still being selfish and arrogant, but I was focused on what was fair and unfair.

Until the Eighties, Oslo was a rather boring town, but it's changed a lot, and is now much more cosmopolitan. If I go downtown, I visit the harbour to see the tall ships and the ferries, and to admire the modern architecture such as the Opera House or the new Astrup Fearnley Museum on the water's edge.

When you're an established name, you know that a children's book will have a pretty good chance of getting picked up. Like Madonna. It's not that I had this great idea. Actually, in my case, it was a great idea.