What is the theme in Alive: The Story of the Andes Survivors by Piers Paul Read?

Another theme would be rescue. The Fairchild crashed at just past three o'clock in the afternoon. Once the shock passed, the survivors began to talk among themselves about a rescue effort. Evening came fast and with it, the cold and darkness. It was apparent that a rescue could not occur in the darkness, so they huddled together to survive the first night. In the early days following the crash, the survivors were confident that they would be rescued.