Sigmund Freud is the founder of psychoanalysis, a revolutionary approach to understanding the human mind. He introduced ideas such as the unconscious mind, defense mechanisms, and the significance of childhood experiences in shaping personality. Freud’s theories on the id, ego, and superego, as well as his work on dream interpretation, transformed psychology, psychiatry, and popular culture. He also developed the concept of talking therapy, encouraging patients to express thoughts and memories freely to uncover underlying psychological issues. While some of his theories remain controversial or debated today, his influence on psychology and the social sciences is immense.