Nicholas Dawidoff's Collision Low Crossers: A Year Inside the Turbulent World of NFL Football may be the best book I've ever read about football. It is certainly the most detailed account of the players inside the helmets and the coaches obscured from an enthralled public by large, laminated playsheets.
Like a brilliant coach, Dawidoff's approach relies on smart tactics and skillful execution. First of all, he outworked the competition, living with the New York Jets all year.