I read this short novel a few months ago, in a proof copy, knowing nothing about the author. As we used to say, it blew my mind. Then I found out about Gaiman via his impressive website, and discovered that he was very well-known in the worlds of fantasy, comic strips and other universes unknown to me. I've since re-read the novel and it's even better than I remembered.
It has echoes of Alice in Wonderland, with elements linking it to various fairy tales - psychologists will have a field day with the dangerous "pretend" mother and father our heroine finds in a looking-glass kind of world that exists alongside the real one.
It's written in a deadpan and unsensational way; the effect is supremely unsettling. There's a real fear aroused by plain descriptions of unspeakable things, many of them to do with eyes.
There are friendly but sinister rodents, and peculiar neighbours. But the real problem turns out to be Coraline's "other" parents, who are truly the stuff of nightmares.
It's a book for all ages, but adults should read it before offering it to anyone younger than about 10. Then again, children are, in many ways, tougher than adults, and it may haunt them less than it has haunted me. It's a good example of the "less is more" principle, and shows how unscary blood and guts are next to chilly, finely-wrought prose, a truly weird setting and a fable that taps into our most uncomfortable fears.