Though they don't always have to be set in fog, weather is incredibly important in ghost stories. As is suspense: you've got to turn the screw very, very slowly.

I have only read very classic traditional English ghost stories, other than Henry James, who wrote some magnificent short ones as well as the longer 'Turn of the Screw.' He, Dickens, and M.R. James are my influences.

I wrote ghost stories because I'd always enjoyed reading them, and they seemed to be fizzling out... I don't take them terribly seriously. It's like a cake, with ingredients.

Suspense is very important. Even though this is humor and they're short stories, that theory of building suspense is still there.

If you were writing a short ghost story, I would say start very quietly and go, 'One, two, three jump.' Or start with a jump and make it jumpier. But with a long story, it must have rises and falls.

Theology is endlessly interesting in that you can study it without believing in anything. I do believe, but you don't have to. I got very caught up in the 11th-century monasticism and the Cistercians. My dissertation was about Aelred of Rievaulx and one of his books.