Konstantin Stanislavski, a Russian theatre practitioner, developed a revolutionary system of actor training in the first half of the 20th century, emphasizing the "art of experiencing" by using conscious thought to access authentic subconscious and emotional processes. This approach evolved from focusing on inner motives and character "tasks" to the more physically grounded "Method of Physical Action," which encouraged improvisation to deeply analyze dramatic situations.

Stanislavski was driven by a desire to revolutionize the superficial theatrical practices of his time, where actors often lacked genuine interaction; he co-founded the Moscow Art Theatre (MAT) in 1898 to move beyond rote line delivery and external displays. His system emerged from rigorous self-analysis and dissatisfaction with earlier external, director-centred techniques, pushing him towards "psychological realism" and pioneering actor-centred pedagogy in theatre studios.

Promoted globally by his students and widely translated writings, Stanislavski's ideas profoundly influenced Western acting, becoming so pervasive that its principles are often used unconsciously as common sense.