The history of strategy:
Strategy & decision making during the Iraq wars
Strategic ThinkingCompetitive Advantage
Positioning theory and Michael Porter
Emergent strategy and Henry MintzbergArticles and Books
Strategy, by B.H. Liddell Hart
Alchemist of War: The Life of Basil Liddell Hart, by Alex Danchev
D-Day, by Stephen Ambrose
Information Rules: A Strategic Guide to the Network Economy, by Shapiro and Varian
Clausewitz on Strategy, by von Ghyczy, von Oetinger, and Bassford
The Art of War , by Sun Tzu (various translations)
Strategy Safari: A Guided Tour Through the Wilds of Strategic Management, by Mintzberg, Ahlstrand, and Lampel
Competitive Advantage: Creating and Sustaining Superior Performance by Michael E. Porter
Strategy & Decision, Chapter 2: "Thinking about Strategic Thinking," by Mark Rhodes.
Ckick here, for an article relating to trade-offs, a key concept in thinking about strategy.