The main theme of Les Misérables, written by Victor Hugo, is the struggle for redemption and the pursuit of justice. The novel explores the lives of various characters, particularly Jean Valjean, who seeks to escape his past as a convict and live a life of virtue. Throughout the story, Hugo delves into themes of moral redemption, the impact of social injustice, and the power of love and compassion. The novel also highlights the harsh realities of poverty and the class struggles in 19th-century France, emphasizing the need for social reform and the importance of empathy and kindness in overcoming societal challenges.