It would be difficult to imagine two more different, yet successful, centennial editions of an old favorite. Polacco sets Casey in a present-day Little League game, framing the familiar text with a brief story: the unsympathetic umpire turns out to be Casey's dad, making sure that the overconfident Casey doesn't ""count his hits before they were pitched"" --a harmless addendum that's good for a chuckle. The transposition works well enough, although some of the mock-heroic verbiage seems overblown when applied to the gangling lad pictured, and 5000 fans are astonishing at a Little League game. The bold, cartoon-like illustrations are full of enthusiastic action and humor, and should have great appeal to children. Moser's elegant edition is a more scholarly production, with fine watercolor portraits based on early-20th-century photos and drawings at the National Baseball Library in Cooperstown. In a graceful afterword, poet Donald Hall discusses Thayer (he showed great promise, but never did anything more important than writing this poem at the age of 25) and places the poem in the context of the history of education, poetry, and baseball; a lovely, wise essay that deserves a wide adult readership.