If the whole book in its Muggle-published form is supposed to be an artifact from the Potterverse, does that mean Dumbledore wrote the introduction years after his supposed death?
Maybe this is another facet of his Will. He writes the commentary well before hand, then writes in his Will “in the event of my death, it is my request that these books should find their way to the muggle population”
Which of course leads to the question: how does Dumbledore - in his will or in person - have the right to publish an exact copy of Harry Potter's personal property?
Dumbledore, break the law? Surely not.
Maybe it was Harry's idea?
Is the commentary not simply in the original book? Seems quite logical that the textbook would include some of the history behind the classification of magical creatures. Dumbledore was a highly intelligent and decorated wizard. Not out of the realm of possibility that he leant commentary to a textbook. I think the book is meant to be the one that Harry actually used in class. Essentially Harry's copy has been duplicated and sold to muggles.
Why do the graffities in the book reference the events up to the fourth book, but not afterwards? Harry and Ron gave up Care of Magical Creatures in their sixth year, but in their fifth they still should have used the book.
It's possible that, that's when their copy was copied.