Brewdude - Couldn't agree with you more re: the Ambrose book. I bought that about a decade ago and the same thing happened to me.
Oh, to get back to the post; I'm currently reading WESTERING MAN by Bil Gilbert. It's an attempt at a biography of "mountain man" Joseph Walker. It's ok, but you can tell that the author is out of his element as he doesn't have a truly informed feel for the fur trade history.