What is the theme in Christ Stopped at Eboli by Carlo Levi?

Carlo believes that Southern Italy contains a different civilization from the rest of Europe. He sees it as composed of peoples who were passed over by the Greeks, the Romans, Christianity and the post-Christian ideologies like Fascism. In some sense, life is the same there as it has always been. The people are pagan, "pre-Christian" and their lives are full of superstition. They believe in devils, ghosts, gnomes, spells, the Virgin Mary, and on and on. Their lives are full of the spirit world and everything has a double nature in that it represents itself and something deeper. Like many ancient civilizations, the people of Gagliano fill their world with the supernatural such that life is constantly accompanied by the mystical.