The One and Only Ivan, by Katherine Applegate. Harper, 2011

Ivan is a silverback gorilla. He lives in a glass cage in a shopping mall, and is part of a mall circus that gives performances several times a day, 365 days a year. When the circus revenue drops and Stella, the aging elephant develops a disabling foot infection, the owner brings in Ruby, a baby elephant,  hoping the cute baby will bring in new customers.

Ruby doesn't adjust well, revenue doesn't increase, and the future of the circus is bleak. With the help of custodial staff, Ivan, who loves to paint pictures, takes matters into his own great hands.

This is not a maudlin story, by any stretch; it is an emotionally powerful paean to animal welfare with appealing characters, both animal and human. It is the 2013 winner of the Newbery Award for children's books.