Konstantin Sergeievich Stanislavski was a Russian actor and theatre director. The Stanislavski system has had a pervasive influence, especially in the period after World War II.
Stanislavski treated theatre-making as a serious endeavour requiring dedication, discipline and integrity. Throughout his life, he subjected his own acting to a process of rigorous artistic self-analysis and reflection. His development of a theorized praxis—in which practice is used as a mode of inquiry and theory as a catalyst for creative development—identifies him as one of the great modern theatre practitioners.
Stanislavski's work was as important to the development of socialist realism in the Soviet Union as it was to that of psychological realism in the United States. It draws on a wide range of influences and ideas, including his study of the modernist and avant-garde developments of his time, Russian formalism, Yoga, Pavlovian behavioural psychology, James-Lange psychophysiology and the aesthetics of Pushkin, Gogol, and Tolstoy. He described his approach as 'spiritual Realism'.