Magic Books is one of the older projects at New Zealand's Human Interface Technology Lab. "When users look at the pages of a real book through a hand held display they can see virtual content superimposed over the real pages. When they see an Augmented Reality (AR) scene they like, the user can fly into the scene and experience it as an immersive virutal environment. In addition the book serves as a focus for collaboration. When several users look at the same book page they can see the AR image from their own viewpoint and when one flys into the virtual model, the other users see her as a virtual character in the scene."
Here is a last year's article by BBC.
