Book excerpt: How does your opponent put that tricky spin on the ball? Why are some serves easier to return than others? The mysteries behind the winning strokes, equipment, and surfaces of the game of tennis are accessibly explained by Howard Brody through the laws of physics. And he gives practical pointers to ways players can use this understanding to advantage in the game. Through extensive laboratory testing and computer modeling, Brody has investigated the physics behind the shape of the tennis racket, the string pattern, the bounce of the tennis ball, the ways a particular court surface can determine the speed of the game, and the many other physical factors involved in tennis.