Hemingway wrote this novel with a very pessimistic mood. There is tragedy behind every action. The mood is also of despair and bitterness. Throughout the novel the war continues either in the foreground or in the background, creating the sense of continuous death that no one can prevent.
Since the novel is written in first person narrative, all the tragedy is seen through Henry's eyes. This makes it much easier for the reader to understand him and sympathize with him in certain situations.
Throughout his novels, Hemingway shows how war is so terrible and that nothing good ever comes out of it. So the main theme of this novel is that war creates or makes a tragedy of everything.
Hemingway uses rain as a metaphor for death. The rain plays a very important role in the expression of emotion and feeling. It is present at every major event in the story, it foreshadows future events, and acts as a projection of the character's emotions.
After the rain's significance is established, simply mentioning that the weather is stormy gives the reader a specific set of emotions. War, love, life, and death are all attached to rain at some point in the novel. By doing this, Hemingway is able to join together situations, which at first consideration could have distinctly different meanings and importance, and create a single, powerful experience.
The novel begins with a description of the situation of the war in Italy at the opening of the story. At the end of that first short chapter, the rain is first mentioned:
"At the start of the winter came the permanent rain and with the rain came cholera. But it was checked and in the end only seven thousand died of it in the army"(Hemingway, 4)
With this first reference to...