Basically, it'd be a book that causes permanent and semi-permanent damage to be "reflected" onto whoever or whatever caused the change. The book would have some form of slow, regenerative qualities, so as to allow for testing and to hopefully elevate it above simply an anomalous item of mild interest.
The title would be something along the lines of "Book Preservation: A Guide to the Proper Care and Handling of Books", although come to think of it now if it's got regenerative properties, It could probably be made to be quite the aged book, though showing none of it. Does carbon dating work like that? I suppose if the mechanics of regenerating were unknown anything's possible in that regard.
Ideally, the main "hook" or whatever you want to call the "meat" or otherwise interesting bit would be the testing log, which could be quite extensive so as to see what exactly happens to entities that affect the book. I had a thought a few tests could be dedicated to using the book as something of a "surgery voodoo-doll", in that making cuts into the book and then sealing the cuts with tape could be a way to preform surgery without the traditional equipment, though at the moment I can't think of any practical usage of that beyond "we don't have to use scalpels and stitches".
The original idea came from thinking about the idea of "defacing a book", taking the "defacing" bit literally, although I came to the conclusion that might be a bit much. Still tossing the idea of something that would cause the book to make someone's face skin (Is the face just the skin or does it include the under bits too?) tear off.
I've thrown together some test ideas. To save on space I've thrown it onto a sandbox http://scpsandbox2.wikidot.com/bakers-dozen-friday