It’s the other way around. ”Var” is used for location, and ”vart” is used for movement. The book is lying still, so it’s ”var”. If you say ”var vargen går”, the wolf is walking around in a fixed location, it’s not moving to that location, so you’d still use ”var”.
That being said, many Swedish speaker don’t make the distinction and use either ”vart” or ”var” for both, but it’s good to start by learning the difference.