This is bookish hobby is HOT. Altered books are some sort of scrap booking that involves books. I just heard of it myself, since it has not blown over to my country yet. I have searched the web to find you the most fun and informative links.
First, what are ‘altered books’? Wikipedia is here to inform you. Click here to learn! There is even a society of ‘Altered Book Artists’, to be found here. Then, if you are ready, click here to get hands on for a how-to. On this page, you will find more projects and techniques.