A small toy mouse on wheels commandingly directs a variety of shapes — squares, circles, ovals, arcs, and rectangles — in different sizes — big, small, thin, tiny — to slide, roll, flip, and fly into the form of a monkey. When the mouse suddenly crashes into the monkey, the shapes reform into a bounding cat. Mouse quickly tames the shapes back into the safer monkey mode. Denise Fleming’s trademark painted-paper collage, uncomplicated text, and comfortable pace make this book an engaging introduction to shapes, sizes, and movement for younger children, as well as to the concepts of parts and wholes, as separate shapes create concrete objects. (Ages 2–6)