On August 21, 2007, Book 10: The City of Kings was released and opened up the city of Annúminas was for players to experience. Unfortunately, the city had been invaded by the forces of Angmar, and players had to fight to keep certain points of the city friendly to them. If they failed, the entire area will fall under the Witch-king's control.
Hunters and Captains both received class reviews, and a new mechanic was introduced called Critter Play. Different than PvMP, Critter Play allowed players to take on new forms in a PvE setting. The first form introduced was that of a chicken. Not to be outdone, Trolls, and Rangers were introduced into PvMP as well as a very large polish pass on PvMP as a whole.
Other new features brought to the game were factions with the major races (with rewards for increasing said faction) and the bartering system which allowed players to turn in certain monster drops for armor rewards. And of course, no Book is complete without a raft of new quests introduced for high level players to grind through.