Bill Walsh, the San Francisco 49ers' greatest coach and perhaps the NFL's as well, agonized when the team he built won a Super Bowl without him.That is how miserable Walsh felt following his retirement from the game. That misery can be a shared one for coaches who suffer failures far more intensely than they enjoy successes. Walsh was in that category.Seth Wickersham's fascinating piece on Walsh explores this and other dynamics of the late coach's makeup through the epic but little-known administrative football handbook Walsh published in retirement.