Supernatural: mystery, suspense or horror books which include elements that defy current understanding of the natural world, including magic, witchcraft and/or crypto-zoological aspects.
“It's a dangerous business, Frodo, going out your door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to.”
-- J.R.R. Tolkien, The Lord of the Rings