One of the themes of Cities of Salt is westernization. Set in an unnamed Arab country, this novel is about the transformation of what was formerly a desert into a modern petroleum-producing state and the effect that this transformation has on the local people. They are immediately suspicious of the American engineers who arrive to look for oil, and they regard the Americans as odd. They even feel that the Americans smell bad. In Harran, the modern city that the Americans construct, the ways of life of the former wadi are forever changed, and the people must adapt to strange new ways that are forced on them quickly, without time for them to process these changes and adapt.

Change and loss forms a significant theme in the novel. The young men who leave the wadi to work in the modern city of Harran are distressed and confused by its ways. The city changes people such as Ibn Rashed, who takes control of the men who go to Harran and who becomes a harsh and exacting leader of them (while he was formerly kind and humorous). An elder named Miteb al-Hathal fears the arrival of the Americans, and he correctly predicts the destruction of the wadi. He escapes into the desert and only appears as a phantom-like figure. He symbolizes the change and loss that westernization and modernization have brought to the local people. The people seem perplexed by the changes introduced into their lives. This change is also symbolized by their introduction to the sea in Harran, as they have never before seen the sea. They react with wonder at the water, but they are also scared of the waves and do not venture very far into the ocean. Even though westernization and modernization introduce them to natural marvels like the sea and to new forms of technology, they are at a loss to make sense of these changes.