My Father's Dragon by Ruth Stiles Gannett
Elmer Elevator rescues a stray cat from outside, and sneaks her milk as often as possible. When his mother kicks the cat out, Elmer decides to run away to Wild Island, an island no one has left alive (minus the cat), and rescue a poor baby dragon. In order to save the dragon, Elmer has to get past many terrifying, wild animals that want him for dinner.
This book is a classic for young readers. The story is fun--Elmer has many creative ways to get past the wild animals. It is also well-illustrated with very fun pictures