There are no neutrals in the Freud wars. Admiration, even complete adulation, on one side; skepticism, even complete disdain, on the other. This is no exaggeration. A psychoanalyst who is currently trying to list Freud in the cultural heroes must contend with a persistent critic who devotes his days to exposing Freud as a charlatan. But on one thing both parties agree: for good or ill, Sigmund Freud, more than any other explorer of the psyche, has shaped the mind of the 20th century. The very power and persistence of his opponents are an odd tribute to the staying power of Freud's ideas.

There is nothing new about such embittered battle; they have slowed Freud's footsteps since he developed the cluster of theories he would give the name of psychoanalysis. Freud's aim in life, as he redefined the way people thought about the world and about themselves, was to "agitate the sleep of mankind." He succeeded in his aim, founding a new field of psychology and creating a new, scientific conception of the individual. His fundamental idea — that all humans are endowed with an unconscious in which strong sexual and aggressive drives, and defenses against them, struggle for supremacy, as it were, behind a person's back — has struck many as a romantic, scientifically unprovable notion. His contention that the catalog of neurotic disturbance by which humans are effected is nearly always the work of sexual unstablization, and that sexual desire starts not in puberty but in infancy, seemed to the respectable nothing less than obscene. His dramatic notion of a universal Oedipus complex, in which (to put a complicated issue too simply) the little boy loves his mother and hates his father, seems more like a literary conceit than a thesis worthy of a scientifically minded psychologist.

Freud was born on May 6, 1856, in the Moravian town of Freiberg, then a part of the Austro-Hungarian Empire, today a part of Czechoslovakia. He was born into a family full of enough complexity and confusion to give him significant material for his ruminations on the individual mind and its connections with others. His mother, Amalia, an assertive, good-looking woman, was twenty years younger than her husband Jacob. She was his third wife; he was forty at Freud's birth. Freud's siblings were two half-brothers, grown-up, a constant reminder of the oddity of his position. His own confusions, hatreds, loves and desires from this period appear to have had significant impact on his later work on development.

Freud first used the term psychoanalysis in 1896, when he was already 40. He had been driven by ambition from his earliest days and encouraged by his dearly parents to think highly of himself. In recognition of his brilliance, his parents privileged him over his sisters and brothers by giving him a room to himself, to study in peace. He did not disappoint them. After an impressive career in school, he was accepted at the age of 17 in the University of Vienna and drifted from one philosophical subject to another until he hit on medicine. The scope of Freud's interests, and of his professional training, was very broad — he always considered himself first and foremost a scientist, endeavouring to extend the compass of human knowledge, and to this end (rather than to the practice of medicine) he enrolled at the medical school at the University of Vienna. His choice was less that of a dedicated doc than of a curious explorer determined to solve some of nature's riddles.

As he pursued his medical researches, he came to the conclusion that the most attractive mysteries were hidden in the complex operations of the mind. Over the winter of 1885-1886, Freud studied in Paris with a French professor of neurology, Jean-Martin Charcot. Under him, Freud practiced and observed hypnosis as a clinical technique, and began to formulate the beginnings of his theory on the mind. Freud went on to make nervous ailments his specialty, concentrating on hysteria. At this point he decided to adopt instead a method suggested by the work of an older Viennese colleague and friend, Josef Breuer, who had discovered that when he encouraged a hysterical patient to talk uninhibitedly about the earliest occurrences of the symptoms, the latter sometimes gradually abated. Working with Breuer, Freud formulated and developed the idea that many neuroses (phobias, hysterical paralyses and pains, some forms of paranoia, etc.) had their origins in deeply traumatic experiences which had occurred in the past life of the patient but which were now forgotten, hidden from consciousness; the treatment was to enable the patient to recall the experience to consciousness, to confront it in a deep way both intellectually and emotionally, and in thus discharging it, to remove the underlying psychological causes of the neurotic symptoms. This technique, and the theory from which it is derived, was given its classical expression in Studies in Hysteria, jointly published by Freud and Breuer in 1895. By then, he had made significant progress in mapping out and defining his own theory of the mind. At the same time he was beginning to write down his dreams, increasingly convinced that they might offer clues to the workings of the unconscious, a notion he borrowed from the Romantics. He saw himself as a scientist taking material both from his patients and from himself. By the mid-1890s, he was launched on a full-developed self-analysis, a cause for which he had no guidelines and no predecessors.

The book that made his reputation in the profession — although it sold poorly — was The Interpretation of Dreams (1900), a masterpiece — part dream analysis, part autobiography, part theory of the mind, part history of contemporary Vienna. The principle that underlay this work was that mental experiences, like physical ones, are part of nature. This meant that Freud could admit no mere accidents in mental procedures. The most meaningless notion, the most casual slip of the tongue, the most fantastic dream, must have a meaning and can be used to discover the often incomprehensible motives we call thinking.

Although the second main point of Freud's psychoanalytic structure, Three Essays on the Theory of Sexuality (1905), further separated him from the mainstream of contemporary psychiatry, he soon found new loyal members. They met weekly to discuss interesting case histories, converting themselves into the Vienna Psychoanalytic Society in 1908. Working on the frontiers of mental science, these often strange pioneers had their quarrels. The two best known "traitors" were Alfred Adler and Carl Jung. Freud did not regret losing Adler, but Jung was something else. Freud was aware that most of his assistants were Jews, and he did not want to turn psychoanalysis into a "Jewish science." Jung, a Swiss from a loyal Protestant background, struck Freud as his logical successor, his "crown prince." The two men were close for several years, but Jung's ambition, and his growing commitment to religion and mysticism — most unwelcome to Freud, who didn't believe the existence of any God — finally drove them apart.

Freud did not want merely to originate a sweeping theory of mental functioning and malfunctioning. He also wanted to develop the rules of psychoanalytic treatments and expand his picture of human nature to include not just the bed but the whole culture. As to the first, he created the mostly silent listener who encourages the subjects to say whatever comes to mind, no matter how foolish, repetitive or outrageous, and who intervenes occasionally to interpret what the patient on the bed is struggling to say. While some adventurous early psychoanalysts thought they could quantify just what proportion of their subjects went away cured, improved or untouched by analytic treatments, such confident list of examples have more recently shown itself unreasonable. The effectiveness of analysis remains a matter of controversy, though the possibility of mixing psychoanalysis and drug treatments is gaining support.

Freud's ventures into culture — history, anthropology, literature, art, sociology, the study of religion — have proved little less controversial, though they retain their fascination and plausibility and continue to enjoy a widespread reputation. In The Future of an Illusion, published in 1927, Freud drew a sharp distinction between religious faith (which is not checkable or correctable) and scientific inquiry (which is both). For himself, this meant the denial of truth-value to any religion whatever. As for politics, he left little doubt and said so plainly in his late — and still best known — essay, "Civilization and Its Discontents" (1930), noting that the human animal, with its greedy needs, must always remain an enemy to organized society, which exists largely to swallow down sexual and aggressive desires. At best, civilized living is a compromise between wishes and repression — not a comfortable theory. It ensures that Freud, taken straight, will never become truly popular, even if today we all speak Freud.

Though much of his scientific work and many of his observations and theories have since been debunked by the modern psychologists, eager to clear their own place in history, Freud singly initiated a new, exciting, dynamic, and often threatening theory of the mind and of the world, a theory which to this day has been taken to the hearts not just of the scientists, but of the people.

In mid-March 1938, when Freud was 81, the Nazis took over Austria, and after some reluctance, he immigrated to England with his wife and his favorite daughter and colleague Anna "to die in freedom." He got his wish, dying not long after the Nazis declared World War II by invading Poland. Listening to an idealistic broadcaster saying this to be the last war, Freud commented coldly, "My last war."