Click HERE to see this thread with all of the graphics, features, and links.

Some parts of it are Canon some parts arn't. Parts of Lost Tales that directly contradict with something stated as true in the Sil or LOTR would not be considered Canon as they are lesser place. However I personally have no problem accepting the LT as a primary source of Canon information provided that it doesn't contradict any other more "reliable" information.

Do you mean The Book of Lost Tales? 'Cause they are definitely not canon, at least in relation to the later stories, as they represent the very idea-germs which later resulted in The Silmarillion.

I mean both The book of the lost tales, and the Unfinished tales. sorry mixed them up. only have the swedish versons see and they have different names so I picked the wrong name it seems. but both of them then. is the unfinished tales book canon?

Ah, I see.

Well, to answer your question....I'd say yes.
They represent Tolkien's mature ideas, but were just never truly finished.