Side mission - A Loss for Words | Act 1 Dungeon Siege III Guide
Last update: 11 May 2016
Notice: mission available only after completing The Search for Survivors!
Right after leaving Chapterhouse you will come across a corpse (M9,1) - based on the information found beside it, it would seem that if you find three lost books and place them on the bookshelf at the Legion Chapterhouse (M4), you would open secret treasure.
The places where you can find the books have been marked on the map (M9,2) and the bookshelf can be found inside the room with stairs in the northern part of Chapterhouse.