One theme in Stephen Vincent Benet's "By the Waters of Babylon" explores how civilizations fare in the wake of widespread nuclear attacks. Another theme explores how John comes of age during his trip across the country.
While studying to become a priest, John has a vision of himself entering the Place of the Gods, which is what New York City is called many generations after nuclear war devastated most of the world. Encouraged by his father to journey to the Place of the Gods, John sets out, passing along the way "Dead Places," or structures that remain radioactive. Though John once went inside a Dead Place with his father, he still fears them and what may happen when he's inside. On his journey, he overcomes his fear and comes of age. He enters these Dead Places and finds a rusty knife in one, a useful tool in a society in which most people hunt with bows and arrows.
In the Place of the Gods, John realizes that it is likely safe. He decides to study the books that remain in the city and take this knowledge home with him. He doesn't realize that doing so puts those who remain at risk for repeating the events that initially sparked the nuclear war. "By the Waters of Babylon" cautions against the fallout of nuclear war and serves as a reminder that without intervention, history repeats itself.
Taking its name from a verse in Psalm 137, "By the Waters of Babylon" examines the physical remains of a post-apocalyptic America, such as towers and monuments, and also the emotional remains of a people shattered by events out of their control.