Sigmund Freud

Born in 1856 in Freiberg, Moravia, and later based in Vienna, he trained as a physician before developing the ideas that made him one of the most famous figures in modern psychology. His work helped establish psychoanalysis, a method of exploring the unconscious mind and the role of childhood experience, repression, and inner conflict in shaping behavior.

Across books, lectures, and clinical work, he introduced concepts that became part of everyday language, including dream interpretation and the basic picture of the mind as driven by forces outside conscious awareness. Even where later scholars challenged his theories, his influence on psychology, psychiatry, literature, and culture remained enormous.

In 1938, after the Nazi annexation of Austria, he left Vienna for London, where he spent the last year of his life. He died in 1939, but his work continues to be read both as a foundation of psychotherapy and as a major chapter in intellectual history.