Stella Adler was an American actress and acting teacher who is widely regarded as one of the most influential figures in American acting. She was a member of the renowned Adler family of actors, which included her father Jacob Adler and her brother Luther Adler. Adler was best known for her teaching methods, which focused on the psychological aspects of acting and emphasized the importance of understanding the motivations of characters. She taught at the Stella Adler Studio of Acting in New York City, which she founded in 1949. Her students included Marlon Brando, Robert De Niro, Warren Beatty, and many other notable actors.