It is really easy to miss. It looks more like a piece of paper than a book.
I searched the library 5 times before I decided to look at each shelf slowly and then I found it. It won't be highlighted even if you are looking at it. You just have to notice one book, or rather, paper, is slightly glowing with particles around it.
Not a glitch, its just that even tho you accepted the quest, the book isn't available to be found yet. (Weird I know.) Once you visit Lavarius, then it magically appears where its supposed to. I get why they don't want you to finish the quest before getting to Lavarius (because of story told in each event).. but why even make it available before you can finish an otherwise 30 second quest. XD