The colorful cap is Will's pride and the delight of the admiring friends he willingly lets try it on. It's useful, too: the long duckbill visor protects him from the sun and even the rain. But, then, alas! Water wilts the visor, causing Will to trip; Mama, however, soon bandages his hurt knee and inadvertently improves the cap by ironing it through a newspaper that imprints the word ``Sport'' on it. The simple, well-paced drama here is perfectly childlike; the cartoon-style illustrations have the vibrant energy and humor of Quentin Blake, with a refreshing Scandinavian flavor. (Picture book. 3-7)