First, go to the storm fortress in Stormwind, which is the king's place, turn left at the first entrepot, and then go to a small garden. On the right, you will find the Royal Library.

There are also some books in the battlefield administrator's room behind the king's throne. . . As for other places, there are also these books, but they are very troublesome and have to run around. I am QS, and I am invincible all the way. I ran away three times and read all the books. .