Expressionism emerged in early 20th century Europe as a reaction against realism, focusing on inner emotions and psychological states. This movement, influenced by Nietzsche and Freud, explored themes of alienation and anxiety in an increasingly mechanized world. August Strindberg, a Swedish playwright, was a key figure in Expressionism's development. His works, like "The Ghost Sonata" and "A Dream Play," used dream-like elements and symbolic characters to explore the human psyche, influencing later Expressionist playwrights.