In a format that echoes that of the Magic Schoolbus titles, Thomson (City Kids in China, 1991, etc.) takes readers behind the scenes at the manufacturer of baseball bats and balls. In the context of a factory tour given to a group of children and a dog, all of whom comment as they go along, author and illustrator limn the materials and the steps involved in making wooden bats, aluminum bats, and hardballs. They also include bits of baseball trivia and lore, a smattering of history (not only when the game became open to African-Americans, but also when the little leagues became open to girls), and some terminology. For young sports enthusiasts, this is an engrossing glimpse at a side of the game to which they may not have given much thought. The pictures, though a bit wooden, are perfectly serviceable and clear, rounding out this pleasant survey of an interesting subject.