This is a terrifying little story with the power of a fairy tale. It takes place over a few days and basically begins with the discovery of a door to another world. It is wonderful that that beginning, in the hands of the right author, can still be thrilling! Coraline enters and immediately encounters rooms very similar to those she just left, she meets people who claim to be her "other" parents, and she explores.
You'll feel uneasy. And in time, so does she.
Coraline is an admirable heroine who is a realistically rendered, though sensible, child. I loved this: "Somewhere inside her Coraline could feel a huge sobbing welling up. And then she stopped it, before it came out." She does amazing things in a short amount of time. Amazing, but absolutely believable.
You'll feel uneasy, and you'll root for her, unless you're a troll or something like that.
A quote by G.K. Chesterton prefaces the book:
Fairy tales are more than true: not because
they tell us that dragons exist, but because
they tell us that dragons can be beaten.
If that inspired Neil Gaiman to write this, he was extraordinarily successful.