The philosopher Jacques Barzun thought that "whoever wants to know the heart and mind of America had better learn baseball." And whoever wants to know baseball had better learn about umpires. As Larry Gerlach points out in The Men in Blue, these arbiters transform competitive chaos into organized sport. They make it possible to "play ball," but nobody loves them. Considering the abuse meted out by fans and players, why would any sane person want to be an umpire? Many reasons emerge in conversations with a dozen former major league arbiters. While nobody loves them, they love the game. Gerlach...