A long-loved poem provides a quality text for an introduction to the rainbow colors plus pink and white. The query that opens each couplet (``What is pink?'') faces a large, flat blob of pure, unequivocal color; on the following spread, the couplet's second line is illustrated with art notable for its simplicity and its focus on the color's true value—a feature not always observed in color books. Unusually attractive and useful. (Picture book. 3-6)