Naturalism is a late-nineteenth-century literary movement that applied deterministic and scientific principles to the depiction of human life. Characters are shown as products of heredity, environment, and social conditions beyond their full control.

Influenced by Darwin, Zola, and others, naturalist writers such as Crane, Norris, and Dreiser portrayed poverty, addiction, and social struggle with clinical detail and without romantic consolation. Plots often end in defeat or mere survival. The tone can be detached or bitterly ironic. Naturalism differs from realism by its more explicit philosophical determinism and its focus on the lower social strata and extreme situations.

The movement was stronger in some national literatures than others and was soon challenged by modernist and other approaches. Its legacy persists in fiction that emphasizes social forces, biological drives, and the limits of individual agency. Reading naturalist works can be bleak, yet they aimed at a truthful accounting of forces that softer literature preferred to ignore.

Fiction that treats human beings as organisms shaped by forces they cannot master belongs to the naturalist tradition.