What got me going in the first place is apparently an error by Tom Shippey in 
J.R.R. Tolkien: Author of the Century, toward the end of his chapter on the mythic dimension, where he says, 
	Quote:
	
	
		| The likelihood is that [Frodo captured and taken to Minas Morgul {sic}] is what Denethor has seen, in a vision controlled by Sauron. | 
	
   So Shippey's wrong about Minas Morgul already, and apparently he's incorrect about Sauron's control.  Hmm... is he also wrong about author of the century? 
