Take a book, leave a book, find a cache. This Little Free Library offers more than just free books, if you can find the hidden cache. Very easy to go undetected by muggles at this spot.
You will need to bring your own pen or pencil to log this cache. Sadly I've been unable to leave one inside the library anymore, as the pen previously provided was being used to deface books. (please note, the cache is not the library itself).