I would suggest crowd-sourcing the book locations. Would you want to create a new thread with "Spoilers" in the title and you and other players can list the locations in which the books have been found? I feel like this would be more satisfying and fun for players because they discovered the locations themselves and worked together towards doing so.
(The book locations is a little different from the hidden achievement guide, because I was planning to give the option to reveal the hidden achievements anyway in the next update of the game.)