This book shares my personal knowledge of tennis. I am an amateur player. I started late, at the age of fifty-four. Sometimes I win, sometimes I lose, but I always understand the game. It was impossible without knowledge. Years ago my frustration in skiing came to an end due to a picture that compared skiing to bicycle riding* It was all I needed for skiing technique to become natural to me and to become an advanced skier in a matter of days. The necessity to find the "bicycle" of tennis to really start playing was obvious to me. My background made it possible. Actually, it was two "bicycles": two elements that constitute a powerful tennis stroke. Once found, my game changed from end to end. Implementing these two elements in a stroke and practicing them, rather than chasing a ball, became a major part of my training. Hitting the ball became a result of a well-designed tennis stroke. Identifying and understanding elements of a tennis stroke require knowledge in physics. Sharing this knowledge in a simple language is all this book is about: illustration of two elements that constitute every powerful tennis stroke and then presenting the forehand, backhand, and service as a combination of these two. *The Anatomy of Skiing by R. J. Sanders, MD