yep you were going the right way. if you continued on the path you were going u would encounter 2 more loot bosses, one a captain, and the other is king gordok. He has a little helper with him who is a healer but is also able to be poly'ed, makeing the fight not so hard. When u kill the king, you become the king and some of the named ogres will give u quests if u did not kill them along the way to the king. Also theres a treasure tribute u get after killing the king....and how good it is depends on how many of the named ogres u killed. Hope this helps, good luck
PS: the books appear to be random off any boss, as the same book has been reported to have dropped from more then 1 boss, meaning they are on a random loot drop rate from any boss i believe.