Soccer is widely regarded as the most popular sport in the world, and the exact velocity, swerve or dip of a soccer ball can be match-deciding. Recent developments in soccer ball manufacturing technology have led to the possibility of radical changes in surface geometry and seam configurations. The consequences of such radical changes to the ball flight can only be fully realized if a detailed understanding of the aerodynamics is gained. Moreover, it is easy to find the non-spinning or low-spinning soccer balls in recent soccer games in which the trajectory of balls represents a characteristic of swing that is called as a knuckle effect or knuckle shot as an unsteady phenomenon. The aim of this book is to further the aerodynamic understanding relating to the knuckle shot. This work uses visualization tests, kicking-robot tests, trajectory measurements, player testing to further the understanding relating to knuckle shot in soccer.