In John Knowles's A Separate Peace, the private war of Gene Forrester parallels that of the theater of World War II. Gene's address to the reader in the final chapter explicates this parallel:
Because it seemed clear that wars were not made by generations and their special stupidites, but that wars were made instead by something ignorant in the human heart.
For, Gene's private evil is the same evil that begins wars. It is the envy and jealousy of others. In the last paragraphs, Gene tells the reader that he was "on active duty all the time at school; I killed my enemy there." However, he was not at war when he served in the army because he did not feel envy and resentment and hatred for the Germans, who were strangers to him. Nevertheless, other people experience "this sighting of the enemy" in places different from Gene, and so metaphoric Maginot Lines are created against their enemies and wars begun. Still, their wars parallel Gene's war because they are created from the same darkness of heart that Gene has harbored. His war, then, is the essential war.