Millions of American baseball fans know, with absolute certainty, that umpires are simply overpaid galoots who are doing an easy job badly. Millions of American baseball fans are wrong.

As They See 'Em is an insider's look at the largely unknown world of professional umpires, the small group of men (and the very occasional woman) who make sure America's favorite pastime is conducted in a manner that is clean, crisp, and true. Bruce Weber, a New York Times reporter, not only interviewed dozens of professional umpires but entered their world, trained to become an umpire, then...