SGTBilko:
Iconian's short-game bible is still scripture (if you add in the apocrypha for the high-spin new clubs and balls), but it is about the short game.
Don't think I've come across such a clear exposition when it comes to hitting longer approach shots from different lies, e.g. if you drive into the rough or a bunker. As far as I can tell, it is a sliding scale based on the percentage of the impediment and the loft of the club, and whether or not it is necessary to switch to a punch shot.
For example, 20/25 rough will take very little distance off of a 9 iron played as a full shot, but at the opposite end of the spectrum the same rough will cut lots of distance off of a 3 iron, or indeed 30/40 rough may be almost unplayable as a full shot with a 3 iron..... etc.