Realism:

"Faithful" representation of life in theater and literature. Realism is based on the conviction of "true" reports of phenomena observable by others. It contrasts with Romanticism, Impressionism, and Expressionism, which are movements based on the belief in internal or ideal truths rather than external truths. Nineteenth century realism was in part a reaction against the excesses of Romanticism and in part a turning away from the classical underpinnings of classical and Romantic literature.

The Harper Handbook to Literature, Second Edition

Major Figures:
Henrik Ibsen
Major works: A Doll's House, The Master Builder, Hedda Gabler
Anton Chekhov
Major works: The Cherry Orchard, The Three Sisters, Uncle Vanya
George Bernard Shaw
Major works: Major Barbara, Man and Superman, Arms and the Man

Realism's grim sister is know as Naturalism, which is best exemplified in the theory of Emile Zola and the plays of August Strindberg.