firstly you have to go into the libary. next sneak past the prefects and go through the door on the right hand side. when you go through the door you will have to get past some more prefects. after that you have to go through the portrait. now look for the thing that you call hedwig with then hedwig will makke a ladder appear go up the ladder and jump from bookcase to bookcase use diffindo on the ropes when you jump on to 3rd bookcase when you do that you will see a book on top of a bookcase jump over to the bookcase and you've got the hogwarts a history book don't come out the way you came out go the other way to get out quicker and you will find the spell skurge.