Darby, the Horse from Hope is a story of how animals can sense and react to the needs of humans. That is why horses have been found to be so successful in providing therapy for people with many different needs. There are horse therapy programs all over the United States. While this story is fiction, what the horses can accomplish is remarkable. Here, Darby deals with the depression experienced by PTSD patients. The story tells how animals can teach patients to feel a sense of worth again and learn more about coping and overcoming the deep sadness with which being in a war has left them. The book also teaches the readers more about the animals and how they can be loving and devoted friends.