I don't have many friends. It's not because I'm a misanthrope. It's because I'm reserved. I'm self-contained. I get all my adventures in my head when I'm writing my books.

My first novel was turned down by half a dozen publishers. And even after having published five or six books, I wasn't making enough money to live on, and was beginning to think I'd have to give up the dream of being a full-time writer.

I am, of course, a frustrated rock star - I'd much rather be a rock star than a writer. Or own a record shop. Still, it's not a bad life, is it? You just sit at a computer and make stuff up.

No matter how many awards you've won or how many sales you've got, come the next book it's still a blank sheet of paper and you're still panicking like hell that you've got nothing new to say.

Witches never existed, except in people’s minds. All there was in the olden days was women and some men who believed in herbal cures and in folklore and in the wish to fly. Witches? We’re all witches in one way or another. Witches was the invention of mankind, son. We’re all witches beneath the skin.

The most difficult part of any crime novel is the plotting. It all begins simply enough, but soon you're dealing with a multitude of linked characters, strands, themes and red herrings - and you need to try to control these unruly elements and weave them into a pattern.

From this height the sleeping city seems like a child's construction, a model which has refused to be constrained by imagination. The volcanic plug might be black Plasticine, the castle balanced solidly atop it a skewed rendition of crenellated building bricks. The orange street lamps are crumpled toffee-wrappers glued to lollipop sticks.