Fact
Library books found around the world are donated in your faction's library through three Friend of the Library quests: Owen Thadd in the Magic Quarter of Undercity (Horde) or Garion Wendell in the Stormwind Mage Tower (Alliance). Rewards per Method's guide: 10 books, Scholarly Pendant or Erudite's Amulet; 20 books (level 20+), Field Researcher's Loop or Philanthropist's Ring; 25 books (level 30+, quest Greater Friend of the Library), Truthseeker's Bow, Crest of Elucidation or Researcher's Night Light. Wowhead lists Greater Friend of the Library as a level 45 quest and all three rewards as item level 45, requiring level 40.