From the time he's a pup, Riptide--Zach's golden retriever--adores the beach: despite local ordinances and the efforts of his family, he turns up daily to explore, patrol, and watch out for swimmers near his Cape Cod territory. In time, the lifeguards' supervisor, Nick, mellows toward him; and after Rip saves a child caught in an especially persistent riptide, Nick relents altogether, calling Rip his ""nineteenth lifeguard."" Weller gives the story, which is based on true events, a graceful, literate telling. Blake's illustrations, apparently oil paintings, are outstanding: though people are clearly not his forte, he is a master of the deep hues and infinite variety of sea and sky, while Rip is remarkably well observed. Fine fare both for dog-lovers and beach-lovers.