Waffling on who wrote A History of Magic

I started re-reading The Prisoner of Azkaban yesterday on the plane back from Toronto and two things jumped out at me.

The opening scene of the novel has Harry hiding under the covers of his bed at Privet Drive, trying to do his summer homework without being discovered by the Dursleys. As you will recall, Harry's uncle and aunt have forbidden him from doing anything related to magic or Hogwarts in their house so we find him, in his room, blankets pulled over his head, quietly reading his text on the history of magic.

First thing that jumped out at me: who the heck is this Adalbert Waffling and when did he write a competing history text to challenge the great Bathilda Bagshot? My paperback copy of the novel clearly states that Harry is reading A History of Magic by Adalbert Waffling. Interestingly enough, it seems that J.K. corrected this error in later editions of the novel. Does that make my little book valuable? And what does that do to the sanctity of the canon if Rowling can publish a book, then go back and "correct" it like this.

I would point out, of course, that Harry's relationship with this particular book (whether written by Waffling or Bagshot) is strange: in book one, he finds the name for his Snowy Owl (Hedwig) in A History; in the third novel, Harry reads this text in order to complete his History of Magic homework; but in later novels Harry claims never to have to opened it.

The second thing that jumped out at me was this: in the original novel, Harry is clearly described as reading A History in the light of a "torch" (which is the English term for what in Canada we call a "flashlight") because he is not allowed to do any magic outside of school. In the film version, however, Harry uses his wand and the "Lumos" spell to provide the light to read the book: a clear breach of magical law. Yet he is never punished for it. He fears that his accidental use of magic (blowing up his aunt) will get him expelled from Hogwarts but feels no compunction about using magic to help him read.

Ahh, if we spent our days finding all the inconsistencies in the movies, we'd never get anything else done, would we? Still, it's fun to point them out when they arise!