This book is based on a true story about a gorilla who lived alone in a mall cage for twenty-seven years before being rescued. You can read about the true Ivan here.
The chapters are only a page or two, which is good for reluctant or young readers. The story is told from Ivan's perspective, which can be a bit confusing for an inexperienced reader.
I liked the book, but I thought it was a bit heavy-handed in parts. It felt like Katherine Applegate was forcing me to care about the animals, rather than letting me develop that relationship with the animals as the story developed. I recommend this book for animal lovers of all ages.