Jean Valjean's transformation from bitter convict to compassionate benefactor is central to the novel. Bishop Myriel's act of mercy in forgiving Valjean's theft becomes the catalyst for his moral rebirth.

Hugo paints an unsparing picture of poverty and inequality in 19th century France, illustrated through characters like Fantine, who is forced into prostitution to feed her daughter, and the Thénardiers, who exploit others to survive.

Love runs through the novel like a thread, from Valjean's paternal devotion to Cosette, to Marius' passionate love for her, to Fantine's selfless love for her daughter, showing how love can provide hope and comfort even in the darkest times.