"Nana" by Émile Zola is a novel that explores the decadence and moral decay of Parisian society in the 19th century. It follows the life of Nana, a beautiful and ambitious young woman, as she navigates the social and economic challenges of her time. The novel provides a vivid portrayal of the excesses and corruption of the Second Empire, using Nana as a symbol of the destructive influence of unchecked desire and hedonism.