This augmented, new edition adds discussion of the bats vertical sweetness gradient, eye-hand cross-dominance, models for the swing of a bat, and accuracy of simulations. The book retains its description of dynamic collisions between baseballs, softballs, and bats, and the intricate modeling of these interactions, using only basic math and physical principles. Veteran baseball science author Terry Bahill explains models for the speed and spin of balls and bats and calculations for bat-ball collisions at a level accessible to most students of the science of baseball. Demystifying the most important factors for understanding bat performance-bat weight, moment of inertia, the coefficient of restitution, and characteristics of humans swinging the bats-Dr. Bahill also explains physical aspects of the optimal bat and the sweet spot.