[The Squatter of Amon Rûdh]

Which is, of course, exactly what I said in my post, only punchier. Obviously the quality of the writing presented in The History of Middle-earth is a matter of opinion, but its authorship is not in any doubt. J.R.R. Tolkien wrote the texts; Christopher Tolkien gathered them together, added an editorial commentary - which he separates clearly from his father's work - and then published it as Unfinished Tales and The History of Middle-earth. The Silmarillion is a much more heavily edited version of the same thing, with the editor making invisible changes to make the book more readable and leaving out his own comments.

For the record, I am not overly concerned with what does or does not constitute the Tolkien 'canon', which is only really useful when debating aspects of JRRT's mythos. I just like to read what he wrote, and I'm prepared to accept that some of his writings differ from others on certain points; just as I'm prepared to accept that Hesiod doesn't agree with Ovid on the details of Greek mythology. In fact, my main reason for responding on this point at all was to point out that J.R.R. Tolkien's writing has a value outside of the details it gives us about his invented universe.

Whatever different permutations of the 'canon' are presented, however, Christopher Tolkien's writing does not belong in it. His opinion deserves respect by virtue of his long association with the stories and their author, but it is not and can never be 'canon' as I understand the word. The question of authorship is, however, completely different from the much vaguer question of canon. Although we'll probably be arguing canon indefinitely, the answer to the question of authorship has been given several times already in this thread.