When it comes to Management, I have to second vellum's advice and go with Drucker:
http://www.amazon.com/Effective-Executive-Definitive-Harperb...
Classic (Mad Men era) of Marketing is ruled by Ogilvy:
http://www.amazon.com/Confessions-Advertising-Man-David-Ogil...
However, I cannot stress enough the role of analytics in modern business strategy/marketing and Kaushik's book is the best:
http://www.amazon.com/Web-Analytics-2-0-Accountability-Centr...