A new book explores how technology and a host of maverick innovators have given rise to an exceptional crop of baseball playersIn a 1940 publicity stunt, the Cleveland Indians’ flamethrowing pitcher, Bob Feller, tested which was faster: One of his own blazing deliveries, or a motorcycle. Feller’s pitching won, hands down. But today, Feller’s once-remarkable speed has become commonplace, even bettered, as major leaguers routinely pass triple figures on the radar gun. The secret to this arms race?...