Johan August Strindberg (22 January 1849 – 14 May 1912) is a Swedish playwright, novelist, poet, essayist and painter.

A prolific writer who often draws directly on his personal experience, Strindberg's career spans four decades, during which time he writes over 60 plays and more than 30 works of fiction, autobiography, history, cultural analysis, and politics.

A bold experimenter and iconoclast throughout, he explores a wide range of dramatic methods and purposes, from naturalistic tragedy, monodrama, and history plays, to his anticipation of expressionist and surrealist dramatic techniques.

From his earliest work, Strindberg develops forms of dramatic action, language, and visual composition so innovative that many are to become technically possible to stage only with the advent of film.

He is considered the "father" of modern Swedish literature and his The Red Room (1879) has frequently been described as the first modern Swedish novel.

In Sweden, Strindberg is both known as a novelist and a playwright, but in most other countries he is almost only known as a playwright.

The Royal Theater rejects his first major play, Master Olof, in 1872; it is not until 1881, at the age of 32, that its première at the New Theater gives him his theatrical breakthrough.

In his plays The Father (1887), Miss Julie (1888), and Creditors (1889), he creates naturalistic dramas that – building on the established accomplishments of Henrik Ibsen's prose problem plays while rejecting their use of the structure of the well-made play — respond to the call-to-arms of Émile Zola's manifesto "Naturalism in the Theatre" (1881) and the example set by André Antoine's newly established Théâtre Libre (opened 1887).

In Miss Julie, characterization replaces plot as the predominant dramatic element (in contrast to melodrama and the well-made play) and the determining role of heredity and the environment on the "vacillating, disintegrated" characters is emphasized.

Strindberg models his short-lived Scandinavian Experimental Theater (1889) in Copenhagen on Antoine's theater and he explores the theory of Naturalism in his essays "On Psychic Murder" (1887), "On Modern Drama and the Modern Theatre" (1889), and a preface to Miss Julie, the last of which is probably the best-known statement of the principles of the theatrical movement.

During the 1890s, he spends significant time abroad engaged in scientific experiments and studies of the occult.

A series of psychotic episodes between 1894 to 1896 (referred to as his "Inferno crisis") lead to his hospitalization and return to Sweden.

Under the influence of the ideas of Emanuel Swedenborg, he resolves after his recovery to become "the Zola of the Occult."

In 1898, he returns to playwriting with To Damascus, which, like The Great Highway (1909), is a dream-play of spiritual pilgrimage.

His A Dream Play (1902) — with its radical attempt to dramatize the workings of the unconscious by means of an abolition of conventional dramatic time and space and the splitting, doubling, merging, and multiplication of its characters – is an important precursor to both expressionism and surrealism.

He also returns to writing historical drama, the genre with which he had begun his playwriting career.

He helps to run the Intimate Theater from 1907, a small-scale theater, modeled on Max Reinhardt's Kammerspielhaus, that staged his chamber plays (such as The Ghost Sonata).