What is the theme in Swan Song by Robert McCammon?

Beauty on the Inside versus beauty on the outside is a theme. After the blasts the world is an ugly, gray place. Sister finds beauty when she discovers the glass ring, Artie finds beauty in his memories of his wife, and Swan finds beauty in Leona's tarot cards. Leona's explanation to Swan of the inside face and outside face is one of the central themes in the novel. As a child, Swan does not understand why beautiful people would be mean and vice versa, and Leona says that God had not figured out how to show people's souls on the outside. Swan misses her long blond hair and can barely stand to look in the mirror after the blasts. Josh jokes that he was never attractive, but now looks downright monstrous. But, they are both beautiful people on the inside, with pure hearts and souls.