Obedience
It is generally believed that a soldier’s purpose is to obey and do it without questioning his superiors. This type of attitude is important because without it, the soldiers on the battlefield would have been hard to control and thus create dangerous situations for everyone. While it is generally believed that a soldier doesn’t need reasons to fight, Doc points out that if a soldier knows why he fights for, then he will be less inclined to desert and cause troubles. It also makes a person fight harder for an ideal that he agrees with.
Coping mechanisms
The author explores the different ways soldiers cope during the war with the horrors they have to see each day and the way this coping mechanisms are describes is a major theme in the novel. For many, joking about the things they experienced was enough to keep themselves sane but for others it was not. Many felt the need to talk about what was happening and they also compared various things such as the weather on the front with the weather in their hometown to keep themselves sane. Other however had to produce elaborate illusions to help themselves deal with the trauma and Berlin is one such example.
Vietnam and war
The action takes place during the Vietnam War, a war during which thousands of Americans were sent to Vietnam and forced to fight for their lives. The war was harsh both on the Americans and the Vietnamese soldiers living there and the author points out just how much both sides were affected by the war. In the end, the reader can reach the conclusion that war is pointless and no one has anything to gain from it. In fact, the war seems to do more damage than good.