i just wanted to inform you guys that i have cleared out Mara's Eye Den before i got the quest to get the book and had it in my inventory when i did get the quest, but the game is still telling me i have to get it and points me to the chest i looted already and wont let me finish the quest.

Same thing happend to me but on a different quest....this quest was a main-storyline quest but all i did was restart my last-saved-game and it worked then.

yea i was going to do the same but it was hours before i got the quest