My System: The Chess Player's Strategic Battle by Aron Nimzowitsch
No book has exerted a greater impact on chess thought over the past 80 years. Variations may come and go, but Nimzowitsch was a seeker after eternal truths and the precepts outlined in this strategic manual have withstood the ravages of time. Breakthroughs in understanding often follow breakthroughs in verbal formulation - Nimzowitsch's skill at translating chess board operations into words was one of the secrets both of his personal success and of the longevity of his system.