As they lay on his famous couch, Sigmund Freud's patients could look around his Vienna office and behold his imposing collection of ancient Greek, Roman and Egyptian figurines. One patient was reminded not of "a doctor's office but rather of an archaeologist's study." The image was apt because the founder of psychoanalysis likened himself to "the archaeologist in his excavations, uncover[ing] layer after layer of the patient's psyche." What Freud (1856-1939) uncovered was a startling portrait of the human as a being unavoidably riven by unconscious sexual urges, guilt, jealousy and aggression. Today, says Yale historian Peter Gay, author of the acclaimed new biography, Freud: A Life for Our Time, "Freud's ideas pervade our culture to such an extent that often we use Freudian language—narcissism, sibling rivalry, ambivalence, neurosis—without even realizing it." Gay, 64, a renowned scholar of 18th- and 19th-century thought and a graduate of the Western New England Institute for Psychoanalysis, availed himself of new material on Freud and tracked down scores of unpublished documents to complete what proved to be the "most intense and demanding" research of any of his 17 books. At his Yale office, Gay discussed this passionate and often brooding genius with associate editor Eric Levin.

What prompted you to undertake a biography, having already written extensively about Freud?

I wanted to say that his life remains relevant and that psychoanalysis still has a lot of validity. I thought there were things being said about Freud that were quite mistaken and even malicious. Also, I wanted to show the close relationship that existed between his inner experiences and his work in a way that had not been done before. The idea is that the person who reads the book will get a kind of informal crash course in psychoanalysis.

What do you see as the principal misconceptions about Freud?

A major one is the belief that Freud was a kind of sex maniac, or at least that all that mattered to him as a theorist was the sexual impulse. Freud never believed that. He did argue that sexuality had been greatly underrated as a cause for neurosis and as a source of energy underlying many kinds of human endeavor. But he always believed there were other basic drives—aggression, for one.

When in Freud's life do you first see evidence that he is destined to become the great archaeologist of the mind?

Even before he graduated from Gymnasium—what we would call high school—in 1873, Freud recognized in himself an unabashed inquisitiveness about human nature. As a psychoanalyst, Freud would later say that scientific curiosity could ultimately be traced back to the sexual curiosity of children. As a child, Freud himself had a very confusing family life.

In what way?

His mother was 20 when he was born. His father, a fairly poor Jewish wool merchant, was 40. His father had been married twice before and had two sons from his first marriage who were about the same age as his attractive new bride. One of Freud's half-brothers had a son who was older than Freud, though he was Freud's nephew. The other half-brother was a bachelor, leading Freud to wonder who belonged in whose bed, since his mother seemed to match up better with this fellow than with his benign old father.

Was Freud conscious of wondering about this at the time?

No. He would only unearth these feelings in the late 1890s as he laboriously analyzed his own dreams and deepest memories. He had been gradually specializing in patients who had certain severe mental symptoms such as loss of language, depressions, hallucinations. The tendency at the time was to ascribe mental events to physical causes, but Freud began looking for psychological causes. In some cases it seemed that early traumatic experiences provided clues to patients' disabilities and that bringing these scenes back to mind under hypnosis had a cathartic effect. But not all patients were hypnotizable. By the mid-1890s Freud felt that uncensored talking was a superior way to tease out the secrets of the unconscious.

Did Freud invent the concept of the unconscious mind?

No. Freud himself made the point that philosophers, poets, even some psychologists had talked about a mental region in which things are stored that we are not aware of. What Freud did was treat it as a part of us that is at work all the time, a part that contains material we can't stand thinking about—lustful, jealous or murderous thoughts that we can't come to terms with and then repress. It's like a maximum security prison in which the inmates try very hard to get out.

What happens when they do?

In the most extreme cases, psychotics might act out their desires, even committing crimes. More commonly you get, for instance, the Freudian slip. One example Freud cited was of the head of the Austrian parliament, about to face a very difficult session, saying, "I hereby declare this session closed—I mean open." This slip means that the unconscious is breaking through.

Freud said there are no accidents; nothing is uncaused. The unconscious also expresses itself in our dreams. When we sleep, self-censorship is relaxed.

What were Freud's feelings about his mother?

The general view is that Freud was absolutely secure in the love of his beautiful young mother, but I argue the opposite. True enough, she adored him and called him her "Golden Siggy." But she kept presenting him with siblings—seven in all. All you have to do is read Shakespeare to see that sibling rivalry was nothing new. But Freud built it into his theory of human development. When Freud was 17 months old, his little brother Julius died in infancy. Freud later recalled welcoming that absence. This is only conjecture now, but I think he was perpetually disturbed about having to share his mother's love with others.

How would you rank the Oedipus complex among his conceptions?

As one of the most remarkable and enduring—and controversial. If you take the little boy as a model, the idea in its simplest form is that the boy regards his father as a rival for his mother's love and therefore unconsciously wishes his father away or perhaps even dead. The pattern can be found in literature as far back as Sophocles' Oedipus Rex. But as Freud points out, the boy not only hates the father but also loves him, and both loves and hates the mother. Freud said this ambivalence is not the monopoly of neurotics but in less spectacular form is the lot of all normal humans.

Freud referred to female sexuality as "the dark continent." Is this where his theories are weakest?

I think so, and these theories—penis envy, for example—have been heavily revised by later analysts. Some of Freud's professions of ignorance about women seem almost willful, as though there were some things he simply did not want to know. Ironically, psychoanalysis is the least sexist profession I know. Freud encouraged women and believed they were as competent at analysis as men. His daughter Anna became one of the world's leading analysts.

What did you discover about the relationship between father and daughter?

Anna, the youngest of Freud and Martha Bernays' six children, stood out from an early age as gifted and sensitive, but also as rather frail and emotional. Freud was very good to his children, but he grew most devoted to Anna. She in turn became his confidante, his colleague and even—following his first operation for cancer of the palate in 1923—his chief nurse. At that point she, rather than his wife, became the center of his life. Their intimacy, though remarkable, was not erotic. It was, however, problematic.

How so?

First, in that Freud was tortured by this problem: On the one hand, he wanted her to get married; on the other, he felt he could not do without her. And she never did get married. Second, in that Freud psychoanalyzed her. He did this at the very time that he scolded another analyst for getting too friendly with one of his patients. I don't know why he did it. My guess is that there might have been a bit of the founder's arrogance there.

There have been reports that Freud was addicted to cocaine. Is this true?

I would say no. He once boasted to Martha that cocaine made him feel like "a big wild man," but it was of interest to Freud less as a recreational drug than as a possible painkiller.

Was he addicted to cigars?

Yes. He finally gave them up in 1930. At that time he said that smoking had served him "as protection and weapon in the combat with life." Back in 1897 he had written to a friend that all addictions, including tobacco, are only substitutes for the "single great habit, the 'primal addiction' "—masturbation.

Is psychoanalysis alive and well?

It seems to me it has become a victim of its own success. In the '50s it was very fashionable. Expectations were excessive, and in the late '60s the love affair turned sour. Young psychiatrists now think that the frontier for the most part is in drugs to treat psychoses, and Freud was not opposed to that at all. He always thought that psychoanalysis was a wonderful way of settling questions about the mind, but he was pessimistic about cures. He did think that by clarifying one's early life and unconscious wishes one gained self-control, which he valued highly. The word he uses to describe what one can achieve through psychoanalytic knowledge is, in fact, "freedom."