Nine chapters (appropriately called innings) in which Mr. Coombs, that peewee league jack of all sport and space, roams far and wide over the diamond from catching the basic facts to fielding the essential questions. Abner Doubleday, he correctly notes, did not invent but helped to standardize the game; the ""most crucial"" struggle is the ""never-ending contest between pitcher and batter""; one day you might be a baseball hero and the next a bum, because it's ""a game of inches."" Coombs also provides generous amounts of prescriptive advice for the aspiring youngster -- ""Avoid the basket catches"" (not everyone is a Willie Mays), give it all you have all the time (""Be in on every play! Don't ever loaf""), ""Don't stand waggling the bat as if threatening to knock the leather off the first pitch that comes your way"" (you'll more than likely whiff). There's nothing here on such new realities as the designated pinch hitter or old ones like bench jockeying or the spitball or Leo the Lip's adage that nice guys finish last, but what Coombs does offer is right over the heart of the plate.