In response to a question on another thread:

He completely revolutionized film acting when he introduced the Stanislavsky system to the medium through actors like Marlon Brando, James Dean, and others. He's considered by most people to be the greatest actor's director who ever lived. He understood subtext and character better than any director I can think of and he knew how to elicit brilliant performances from his actors without their knowing he was doing it. Being a master psychologist, he was able to make them feel, always, that it was their doing. In Kazan's twenty films, his performers received 21 Oscar nominations and won 9. He himself won two Oscars and received several other nominations, including for original screenplay ("America, America"). He also directed several great Tony Award winning plays, among them "Death of a Salesman," "Cat on a Hot Tin Roof," and " A Streetcar Named Desire." He was one of the three orginal founders of the Actors Studio (the others being Cheryl Crawford and Robert Lewis). He was the first artistic director of the Lincoln Center Theatre.

Because he began his career as a theatre director, he had a refined since of blocking for camera. And he was one of the first directors to fully, artistically exploit the wide screen process with his dynamic compositions in "East of Eden." He understood text as well as any writer he ever worked with, and helped writers as great as Tennesse Williams shape their material for the better.

And no actor, writer, or crew member who ever ever worked with him ever considered him to be anything but brilliant. Even Arthur Miller, who severed their relationship after HUAC, resumed it years later when he asked Kazan to direct the world premier of his play, "After the Fall," at the Lincoln Center. And Barbara Bel Geddes, another HUAC casualty, starred in "Cat on a Hot Tin Roof," which Kazan directed on Broadway.

He also wrote several successful novels after he quit directing.

These are just a few of the things that demonstrate his indisputable brilliance. . .