It was a bit unimaginable when I began that I'd ever get to 25 books. But it was also unimaginable how much crime-writing would have changed.

We weren't dirt poor, but there was no spare money kicking around. While it was very much understood that the way to a better life was through education, books were a luxury we couldn't afford. But when I was six, we actually moved opposite the central library, and that became my home from home.

I said to Ruth Rendell, 'When you've written as many books as you have, it's easier.' She said, 'No dear, it gets harder'.

If you don't make the best-seller list, if you don't get shortlisted for any prizes, it's goodbye.

The thing is that quite a few of my books have ended up as they are because of conversations I've had over the years with forensic scientists.

Walking by water frees your creativity. I don't know how it works - there's something about it that's liberating.