No wait, before we sink into the slush pile....
For Fowler's Modern English Usage, I recommend the second edition -- which would mean any of the many reprints revised and edited by Sir Ernest Gowers. The one I have is dated 1965. I think he kept updating it in subsequent reprints but in all of them stayed faithful, for the most part, to Fowler's original text. Yes, stay away from the third edition; it is a full rewrite, and an inferior and needless one at that, and so it should not even be using the same title; "Fowler's" is not a franchise, for heaven's sake.
I will check out Mary Norris's book. I had a childhood neighbor/friend/classmate who grew up in a theater family and somehow wound up at that same copy desk with Mary Norris, where she has worked for many years now. Your recommendation reminds me that maybe I should go to our upcoming class reunion after all, if only so I can talk with my old friend and ask her how she wound up with my dream job. I mean, all my memories of her involved Broadway show tunes -- I remember her belting "Sam, You Made the Pants Too Long" at age 9 for the school talent show -- and not anything involving English syntax.