Arcane Tome

Arcane Tomes, along with Firewing Signets and Sunfury Signets, are items used to get reputation with the Scryers in Shattrath City.

Source
This item is dropped by higher level Blood Elves in Shadowmoon Valley, Netherstorm and The Isle of Quel'Danas. Contrary to popular belief, Blood Elves in Firewing Point also drop Arcane Tomes, despite the description of, which clearly states that they drop from higher level mobs.

As a quest objective

 * (Repeatable)
 * (Repeatable)