Who was Sigmund Freud and what did he contribute to psychology?

Sigmund Freud was an Austrian neurologist who founded psychoanalysis, the first comprehensive theory of personality and psychotherapy. He proposed that behavior is driven by unconscious conflicts, often rooted in childhood experiences and sexual or aggressive instincts. Freud's structural model divides the mind into the id seeking immediate pleasure, the ego mediating between desires and reality, and the superego representing moral standards. He described defense mechanisms like repression, projection, and displacement. ---