It is reassuring to be in the company of Lionni's mice again. These inquisitive, clever animal characters prove once more the value of the fable as storytelling device, especially when it is simply told and beautifully illustrated. Tillie, one of a band of mice, is confined, not unhappily, to a meadow behind a long, high wall. Although there is companionship and plenty to eat, Tillie longs to discover the unknown world beyond the wall. In her reveries she creates an imaginary place peopled with fantastic creatures, giving Lionni an opportunity to display his coloristic artistry. It takes all of Tillie's determination and resourcefulness to overcome the complacency of her companions and eventually to find a way to the other side of the wall. The fact that Tillie is the youngest mouse, and a female, lends substance to the message that strength of character and leadership qualities will surface when a challenge arises. The simplicity of line and shape in the full-color collage illustrations enhance the mood of the text. This integration of art and prose, and the message that both convey, provide children with a superior picture book that can be enjoyed on several levels. Invite Tillie and her friends to join other Lionni favorites on the picture book shelves. As with Lionni's other books, this one should be a perennial favorite for primary grade story hours. --Martha Rosen, Edgewood School, Scarsdale, N.Y. Copyright 1989 Reed Business Information, Inc.