Freud was born to a Jewish family in Freiberg, Moravia (now Pribor, Czech Republic), the son of Jakob Freud, a wool merchant, and his wife Amalie Nathansohn. Intensely intellectual as a child, at the age of 17 he began to study medicine at the University of Vienna. After graduating, in 1882, he joined the staff of the Vienna General Hospital, specializing in neurology, and collaborating with the Austrian neurologist Josef Breuer in the treatment of hysteria by the recall of painful experiences under hypnosis. He then studied in Paris (1883-5) under Jean Martin Charcot, and it was there that he changed from neurology to psychopathology, the branch of psychology that deals with the abnormal workings of the mind. Returning to Vienna, in 1886 he married Martha Bernys, to whom he had been engaged, but whom he had not seen for two years. They had six children, and she remained a constant support throughtout his often trbulent and controversial career.

In private practice Freud began to develop the technique of conversational 'free association', finding hypnosis inadequate. He refined psychoanalysis as a method of treatment, interpreting the data of childhood and dream recollection, and allowing the patient to express thoughts in a state of relaxed consciousness. In 1893 he published a paper with Breuer, which was expanded in 1895 to Studien über Hysterie (Studies in Heysteia), marking the beginnings of psychoanalysis. Recalling significant events from his own childhood (triggered by the death of his father in 1896) and from those of his patients, he becamae convinced, despite his own puritan sensibilties, of the certainty of infantile sexuality. The gave rise to his concept of the 'Oedipus complex', the name he gave to the erotic feelings of a son for his mother, and its associated sense of competitiion with the father. Such a view isolated Freud from Breuer and from the medical profession in general, who looked on his theory with incredulity and hostility.

One of the means he used to analyse himself was to decode his dreams in terms of their organization and meaning or purpose. His major work, Die Traumdeutung (1900, The Interpretation of Dreams), argued that dreams are disguised wish-fulfilment - manifestations of repressed sexual desires and evergy. In 1902 he was appointed to a chair of neuropathology in Vienna, despite widespread academic anti-Semitism, and began to gather disciples. He started a weekly seminar (the original 'Psychological Wednesday Society') in his home with such kindred minds as Alfred Adler, and produced further crucial works: Zur Psychopathologie des Altagslebens (1904, The Psychpathology of Everyday Life), and Drei Abhandlungen zur Sexualtheorie (1905, Three Essays on the Theory of Sexuality), which met with intense and uncomprehending opposition.

In 1908 the group that attended his weekly seminars called themselves the Vienna Psychoanalytical Society, and in 1910 the International Psychoanalytical Association, with Carl Jung as the first president. Both Adler and Jung broke with Freud to develop their own theories in 1911 and 1913 respectively.

Undeterred, Freud produced Totem und Tabu (1913, Totem and Taboo), Jenseits des Lustprinzips (1920, Beyond the Pleasure Principle), and Das Ich und das Es (1923, The Ego and the Id), elaborating his theories of the division of the unconsious mind into the 'id', the 'ego', and the 'super-ego'. In 1927 he published a controversial view of religion, Die Zukunft einer Illusion (The Future of an Illusion), and in 1930 was awarded the prestigious Goethe Prize. It was not until then that his work ceased to arouse active opppostion form public bodies.

In collaboration with Albert Einstein, he published Warum Krieg? (Why War?) in 1933. At the same time, Hitler effectively banned psychoanalysis, and after Austria had been overrun, Freud and his family were extricated from the hands of the Gestapo and allowed to emigrate. He settled in Hampstead, London, where he died a year later as a result of cancer of the jaw and cheek, for which he had undergone more than 30 operations since its diagnosis in 1923. His daughter, Anna, went on to become the founder of child psychoanalysis.

Although many psychiatrists and psychologists now disagree with some of Freud's ideas, his insight has had strong and useful influences in many fields: his research into unconscious drives has had a significant impact on criminology, sociology, and anthropology. His work changed the way many people think about personality and motivation, and caused a re-evaluation of the importance which attaches to early family relationships and thier effect on the developing personality. But his most important influence was to inspire modern psychiatry by his examination of mental illness. However, although he inspired fields of scientific study, ofteen his methods were not very scientific. In fact, he described himself to his friend Wilhem Fliess not as a scientist but as an 'adventurer' and his methods were often fearlessly unscientific, partly because of the new and controversial nature of his study. The main weakness of Freudian analysis is that, in order to explore the abnormal, he had to establish what 'normal' was. To do this he looked to himself, and extrapolated from his own experiences into a general theory. This established male sexualitty as the norm, and made for a phallocentric theory in which woman could only be accommodated by his theory of penis envy.

However, despite the obvious problems with Freud's work, his great success was to put sexuality on the scientific agenda, liberating its study from the social taboos that had bedevilled his work and made him such a controversial figure. His use in analysis of mythologies, literature, and art also established the role of culture in the development of personality, and vice versa. This partially accounted for the broad base of interst his work inspired in the artists (especially the Surrealists) and writers who followed him. His influence extended so broadly into modern life that, in 1945, the Oscar-winning film Spellbound presented as popular entertainment a plot which was a psychological thriller solved through psycholanlytic detective work and dream analysis against sets designed by the great Surrealist, Salvador Dali.