Where are the missing books?
Solution 1:
If you are talking about Skyrim, the books should be located on the pedestals in around the room. See Hitting the Books. If you still can't find them and you're on a PC, accessing the console and using 'setstage MG03 200' should automatically complete the quest and lead you on to the next one.
Solution 2:
The books are sometimes strewn about on the floor during the fight. Look closely on the floor, you will find the missing books somewhere on the floor.