"Oh no! See it go!" A boy loses a bicycle wheel, which then careens through the book ("pa-da-rump pa-da-rump pa-da-rump-pump-pump"), with rhymed couplets describing its progress and onomatopoetic words placed at strategic points in the illustrations to cheer it on. It meets its match with a bill that reverses it, while the book turns 90 degrees to provide a long return descent past the scenes from the outgoing journey--seen in deeper tones since it is now night--back to the boy, who is able to ride the bike home. At first glance, this is pure fun; but--like the best fun--there's more to it: practice with prepositions, rhymes, and other concepts, as well as Hurd's joyously lively art, using bold forms and colors that modulate from bright noonday to sober night through a series of changes as artful as a Bach invention. A beguiling variation on the familiar theme of mischievous runaway.