A baseball is formed by winding yarn around a small sphere of cork. The ball is then covered with two interlocking pieces of white cowhide, which are tightly stitched together. The mass and circumference of a regulation baseball are 5oz and 9in (i.e., about and ), respectively. In the major leagues, the ball is pitched a distance of 60 feet 6 inches (i.e., m), towards the hitter, at speeds which typically lie in the range 60 to 100 mph (i.e., about 30 to 45 ). As is well-known to baseball fans, there are a surprising variety of different pitches. ``Sliders'' deviate sideways through the air. ``Curveballs'' deviate sideways, but also dip unusually rapidly. Conversely, ``fastballs'' dip unusually slowly. Finally, the mysterious ``knuckleball'' can weave from side to side as it moves towards the hitter. How is all this bizarre behaviour possible? Let us investigate.