How do you find the secret room in boo level on regular Mario 64?

The secret room in the Haunted house requires that you unlock the vanish cap. The vanish cap level can be found under the moat on the left side of the bridge (from where you start out) After you've gotten the vanish cap, go into the Haunted house (see related questions) and go up the stairs. Go to the right, and enter the last door on your right. Avoid the killer books that come from the bookcase, go around the corner, and through the door. (Note:the floor does drop in the middle) Get the vanish cap at the end of the hall. Run back through, to the bookcase, wall kick up to the platform, and run toward the camera. Look for a wall that has a picture of a boo on it. Go through the wall, and you are in the secret room. (Note: there is a giant eye and a boo in this room. To defeat the eye, make sure it is looking at you and run around until it gets dizzy. To defeat the boo, see related links)