The Art of War is one of the oldest and most successful books on military strategy in the world. It has had a huge influence on Eastern military thinking, business tactics, and beyond. Sun Tzu recognized the importance of positioning in strategy and that position is affected both by objective conditions in the physical environment and the subjective opinions of competitive actors in that environment. He taught that strategy was not planning in the sense of working through a to-do list, but rather that it requires quick and appropriate responses to changing conditions. Planning works in a controlled environment, but in a competitive environment, competing plans collide, creating unexpected situations. The Art of War has also been applied to business and managerial strategies.