In the Silversky Palace, find Tobias (he is a mage near the palace dungeon). Say Book of Warfare and Yes and he will sell you one for 15.000 gold pieces.

Take the book to Adriana (she is the armor penetration teacher east of the pot shop). Say Book of Warfare and she'll agree to trade it for the Blade of Sharpness. Say Yes and you'll do the trade.

Gain :

• Blade of Sharpness

Note: You can do this quest as many times as you want