The One and Only Ivan by Katherine Applegate

This is a wonderful story about an easy going gorilla called Ivan, who lives out his days viewing the world from his cage in a small circus. His two companions are an elephant named Stella and a stray dog who sleeps in Ivan's cage at night and keeps him company. 
This simply-told, easy to read story about friendship will surely take its place alongside the animal favourites such as Charlotte's Web and Sheep Pig. Like these classics Ivan has his own story to tell and a brave mission to undertake if he is to make a difference for some new young arrivals at the Exit 8 Big Top Mall.

Highly recommended!