YOUR INSIDES

The author of the wildly popular ``Magic School Bus'' series introduces kids to their own bones, muscles, joints, digestive tract, lungs, heart, and nervous system. Each body part is described in a few sentences on a double spread, cheerily illustrated with active multiethnic children demonstrating the points made. Graphic headings (``Your Blood Is a Delivery Service''; ``Your Brain Is Your Control Center'') grab attention and help clarify what follows. Explanations are most complete for mechanical parts like muscles and joints; more complex processes like digestion are abbreviated, but accurate as far as they go. Children will especially enjoy a sequence of four see-through pages (skin, muscles and bones, heart and lungs, stomach and intestine- -with ``Your Brain and Nerves'' on the opaque page that follows), though their usefulness is somewhat limited since some organs are omitted and labeling is scanty. Still, a great deal of clearly presented information, in a lighthearted format that's sure to appeal to kids. (Nonfiction. 6-10)