PreS-Gr 2 An unfortunate choice of ``grocery store'' illustrations and generally flat format detract from what could be an appealing story. On the day of a big parade, Mr. Downs nods off after selling most of his balloon supply, but his helium hose keeps hissing. In an effort to stop the noise, his dog puts the hose inside Mr. Downs' coat, and Mr. Downs and Willy float skyward. As the unsuspecting pair soar along with the parade balloons, a policeman, a fireman and a cowboy try, frantically, to bring them down. Finally, Mr. Downs drifts by his own bedroom window. Willy barks; Mrs. Downs awakens and pulls them both through the window to safety. The watercolor illustrations are cartoon-like and not particularly eye-catching but are full of funny details. Easy enough for many first-grade readers, this story cries for a more aesthetically pleasing format. Barbara McGinn, Oak Hill Elementary School Media Center, Severna Park, Md.