Where is the third book in the quest Hitting the books?

I have

killed the Caller

and in that room I've found two of the three books on the two pillars in the side rooms. Where is the third book? The central pillar was empty. Can't find it anywhere.

Solution 1:

I found it just over the body of the Caller herself. Maybe she had it on her. Or maybe some action made ejected it from the pillar.

Solution 2:

Yeah, I had exactly this issue.

By deselecting every other active quest, the third book then had a marker over it on re-entering the Ritual room. It was almost the same colour as the floor and would have been impossible to spot without this quest marker appearing just over it.

I'm pretty sure that marker wasn't over the third book when I'd been in the room previously (when I had multiple active quests).

Solution 3:

The quest highlights the books with a giant arrow. I found two on a pedestal, and the third one knocked over by the fighting. Since they get thrown around so easily by all the magic, it is possible it was knocked through a wall.

Try to grab the books before the fighting starts to make sure.

Solution 4:

you can use clairvoyance to locate the last book if it fell through the floor or a wall.

Solution 5:

I had the same problem at the end of the battle. If you select the journal and set the quest to track it will lead you to the book - my missing book was on the floor in a dark corner after the fight.