What Is a Bird? (The Animal Kingdom)
What Is an Amphibian? (The Animal Kingdom)
What Is a Fish? (The Animal Kingdom)
What Is a Mammal? (The Animal Kingdom)
What Is a Reptile? (The Animal Kingdom)
Animal Classification : A Guide to Vertebrates
Animals With Backbones (Kid's Guide to the Classification of Living Things)
e.Encyclopedia Animal
Classification of Animals (Sci-Hi: Life Science)
Disney Learning Wonderful World of Animals
The Animal Kingdom (Classification)
Nematodes, Leeches, and Other Worms (Animal Kingdom Classification)
Tree Frogs, Mud Puppies, and Other Amphibians (Animal Kingdom Classification)
Encyclopedia of Animals
First Animal Encyclopedia (Dk First Reference)
National Geographic Encyclopedia of Animals
Visual Encyclopedia of Animals
Living Processes: Animal Variation and Classification
One Million Things: Animal Life
My Big Animal World Book (My Big Reference)