That was the very centre of his genius - he invented things that anyone could have thought of, and men who can invent things that anyone could have thought of are very rare men.

And what do you really do? asked Tiffany. The thin witch hesitatied for a moment, and then: We look to ... the edges, said Mistress Weatherwax. There's a lot of edges, more than people know. Between life and death, this world and the next, night and day, right and wrong ... an' they need watchin'. We watch 'em, we guard the sum of things. And we never ask for any reward. That's important.

I think when people mean that Discworld books have become darker they really mean the series is growing up. In 'The Colour of Magic' most of the city is set alight. It's a joke, in much the same way that the Earth is destroyed almost at the start of Douglas Adams's 'The Hitchhikers Guide to the Galaxy.'

It is always useful to face an enemy who is prepared to die for his country," he read. "This means that both you and he have exactly the same aim in mind.

This is where the gods play games with the lives of men, on a board which is at one and the same time a simple playing area and the whole world. And Fate always wins.

The English were notoriously unenthusiastic about burning witches. I suppose ours were too soggy.

People don't like to say Horror so they say Dark Fantasy because that's Horror wearing a collar and tie.