LiveScience has a nice article on the science of pitches, speed and trajectory. The first part explains how it is physically impossible as a hitter to track a pitch all the way to the plate, and the second part explains why it's smarter to catch a fly ball running, rather than standing still.
Legendary hitting coach Charlie Lau on hitting a knuckleball: "There are two theories on hitting a knuckleball. Unfortunately, neither of them works."
My other favorite Charlie Lau quote: "Nobody should hit .200. Anybody should hit .250"