Sigmund Freud was a famous Austrian neurologist who founded psychoanalysis. Some key aspects of his theory include that mental life is divided into the conscious and unconscious minds. The unconscious contains drives and urges beyond our awareness, and can be revealed through dreams, slips of the tongue, and other mechanisms. Freud believed psychopathology arises from unconscious conflicts between the id, ego, and superego. He developed techniques like free association and analysis of transference to treat disorders like hysteria and neuroses. Psychoanalysis examines early childhood development and the influence of sexuality and aggression on personality formation.