History of Magic was the dullest subject on their schedule. Professor Binns, who taught it, was their only ghost teacher, and the most exciting thing that ever happened in his classes was his entering the room through the blackboard. Ancient and shriveled, many people said he hadn't noticed he was dead. He had simply got up to teach one day and left his body behind him in an armchair in front of the staff room fire; his routine had not varied in the slightest since.