Thinking, Fast and Slow by Daniel Kahneman. A Nobel Prize-winning psychologist draws on years of research to introduce his "machinery of the mind" model on human decision making to reveal the faults and capabilities of intuitive versus logical thinking, providing insights into such topics as optimism, the unpredictability of happiness and the psychological pitfalls of risk-taking.
Compiled more than two thousand years ago by a mysterious warrior-philosopher, The Art of War is still perhaps the most prestigious and influential book of strategy in the world today. Its aim is invincibility, victory without battle, and unassailable strength through understanding of the physics, politics, and psychology of conflict.
Fascinating and well-written book. Update: Well, that's what I wrote then. Now, of course, we know that he invented a lot of the quotes that "proved" his theories and his ideas have been largely discredited.