Sigmund Freud

Sigmund Freud is the most famous name in psychology. As the founder of psychoanalysis, he introduced the world to the concepts of the unconscious, defense mechanisms, and the importance of early childhood experiences. While many of his specific theories have been debunked or significantly modified by modern science, his impact on the cultural and clinical landscape is undeniable. He popularized the idea of 'talk therapy' and brought mental health into the public consciousness.

His work remains a critical historical reference point for understanding the evolution of modern psychotherapy and the human psyche.