Library books are found all around Azeroth, and upon handing them in, you can claim different rewards at different levels. The quest for 25 books requires level 30.
Number of BooksQuestRewards (Choose One)
10Friend of the LibraryScholarly Pendant
Erudite's Amulet
20Greater Friend of the LibraryField Researcher's Loop
Philanthropist's Ring
25Greater Friend of the LibraryTruthseeker's Bow
Crest of Elucidation
Researcher's Night Light
It's possible that, since the other two quest rewards require level 40, the bow is also intended to be level-locked; for now, though, Hunters might want to take a trip around Azeroth to look for some overdue library books.
To hand in a book, you need to visit your Faction Librarian.
Location
Stormwind City, Mage Tower
/way 49.0 86.4
Garion Wendell, inside the Mage Tower
Garion Wendell
Location
Undercity, The Magic Quarter
/way 74.0 32.4
Owen Thadd In the Magic Quarter
Owen Thadd
Our Library Book Collection guide has an extensive list of known Library Book locations and you can also browse our World Map Tool for the most up to date locations with data coming directly from the Wowhead Looter Client.
