I would say that one of the major themes of Hillenbrand's work is the struggle to survive. Louis embodies this at different points in the work. The human need to survive is a driving force behind Louis' war narrative, in particular his time as a prisoner of war. Along these lines, I think that the theme of redemption is another major element that constructs the work. Louis' time when he returns is one of loss and a sense of forlornness. Louis is cut adrift as a veteran, seeking to make sense of what happened to him in the war and what is in front of him after it. His need to reclaim his life and demonstrate the tenets of redemption are extremely significant to the novel and to his own characterization. Another theme that is connected to this is one of forgiveness and the human capacity to forgive. Louis recognizes this in his return to Japan as well as his attitude towards his captors. In these themes, one sees Hillenbrand's exploration of the human predicament through Louis. The drive for survival, the intrinsically human idea of redemption, and the capacity for forgiveness are all a part of what Louis experiences in the novel and represent the major themes with it.