1920s: WWI is a notorious war. There was no clear villainous enemy, as in the fascists of WWII. It was terribly inefficient. It was considered then how the Viet Nam war is considered today, a fight that used soldiers sorely and traumatically. It ate up young men with all the efficiency of a giant thresher. The term "shell shock" was invented to name the hysteria and psychosis that the war induced in so many of the soldiers.

1990s: Countries like the U.S. which have technologically sophisticated warheads are now able to conduct "limited" wars. In contrast to WWI, the recent U.S. and European fighting against Serbia was conducted entirely from the air. Things and not people were the primary targets.

1930s: The Spain of Hemingway's story suffered a great deal during the 1930s. The country, moving to more fully democratic rule, had...