Resilience in Adversity: A main them 0f the story is how Louie displays unwavering courage and a belief that he can survive anything. It is shown through his ideas and how he interacts with fellow soldiers. He steals food from the Japanese, hides a journal in his bed, and helps other prisoners when he can. All of these point towards how he rebelled against the Japanese and gave his fellow soldiers courage during their incarceration.
Optimism: Another theme that is important to the book is optimism. While it aligns with resilience somewhat, it is also very different. IN the story, Louie is always looking for the next good thing to happen and the next opportunity to take advantage of. This is the optimism that is so important to him because he does not dwell on what has happened or the negative circumstances. Instead, he thinks of his current situation and how he can improve on what he is doing every day.
Faith and belief in God: This theme is another important one in the story because of how Louie relies on his prayers when they are stranded in the ocean. He says that he will give his life to God if they get through the ordeal. They do survive the ocean but are captured and put into the POW camps. There Louie struggles to figure out how God could put men in those situations and he continually struggles with this concept for a long time in his life. It is only later in life that he hears a sermon from Billy Graham and realizes the anger and bitterness he has kept within himself about the time in POW camps and how he was treated.