A First Look at Animals With Backbones and A First Look at Animals Without Backbones by Millicent E Selsam
 
There are more than a million different kinds of animals in the world. Only 50,000 of these have backbones, and are called vertebrates. The rest are animals without backbones, called invertebrates. This book gives an overall view of these animals and shows the young reader how to distinguish between the major groups. It was awarded Outstanding Science Book for Children.