Master Sun’s problem—first posed by Sun Bin, a Chinese military strategist and supposed descendent of Sun Tzu, the legendary author of “The Art of War”—is an ancient strategy question whose elegant simplicity conceals a fiendishly difficult mathematical puzzle. The problem was largely ignored for 2,000 years until a college friend of Dana Mackenzie revived it—and in doing so, rekindled Mackenzie’s passion for mathematics. “Master Sun’s Problem” is Mackenzie’s entertaining account of how, to his