World of Warcraft: Wolfheart is a Cataclysm expansion tie-in book by New York Times Best Selling Author Richard A. Knaak.
The book description reveals the uneasy interaction between King Varian Wrynn and the Worgen King Genn Greymane; and the re-introduction of Warden Maiev Shadowsong into continuity.
Maiev was last seen in the Burning Crusade expansion where she helped players defeat Illidan Stormrage at the Black Temple dungeon. Nothing had been known of the character for the past five years since the Burning Crusade expansion until now.
Malfurion and Tyrande assign Maiev to hunt down the assassin of a highborne in the outskirts of Darnassus.
Blizzplanet has a description of this upcoming book to be published on September 13, 2011.