An ingenious format for rehearsing a favorite topic: in pleasantly cadenced, repetitive verse, newcomer Wolf describes Peter's survey of the trucks he sees in his city neighborhood and on a visit to the country. Questioning their drivers, he learns (Epaminandos-style) that, despite the picture on its door, the milkman's truck contains no cows, just milk; the gasoline truck holds not milk, but gas, and so on until, coming satisfyingly full circle, he finds a farmer's truck full of cows. Using sturdy broken lines and bright added color, Bowman depicts the trucks in bold but loving detail while providing a multiracial cast of men and women to drive them. Just right for the ``Vroom vrooom'' set. (Picture book. 2-6)