The Nu in the eastern back room will explain the secret of the magic books. You must open them in the order water (northwest), wind (southeast), fire (center) to open a secret room.
Once you've learned the Nu's scratch-point in Zeal Palace, you can come back here and speak to the Nu in the research room to earn a Magic Tab. Don't miss the Speed Tab that is oddly hidden in that room, which you can see on the bookshelf outside.
After the Mountain of Woe, the Nu here will have more goods for sale. He won't sell them to you if you tell him that you have Schala's Pendant, though. In fact, you must leave town and return before he'll speak to you again if you say so.