Or maybe the book has created a world that is special and unique and so well-described that you feel as if you're living in it long after you have set the book down. I've discovered that books with this sort of "atmosphere" turn out to be some of my favorites, books that stick with me for years after I've read them.
The Harry Potter books by J.K. Rowling

The Night Circus by Erin Morgenstern

Memoirs of a Geisha by Arthur Golden

Jonathan Strange & Mr. Norrell by Susanna Clarke
