Have you ever found "The Book"?

Hidden in the depths of the Feinberg Library collection is "The Book". It was not purchased by the library. It is not cataloged. It doesn't have a call number. But it travels freely through the building. We do not know from whence it came. But its rules are simple. If you happen across the book, you must write in it and then put it back somewhere in the library for the next person to find it.