The Interpretation of Dreams, Freud’s magnum opus, was first published in 1899 but was given a copyright date of 1900 to associate it with the new century. This proved prophetic, as the book’s impact on twentieth-century thought and culture has been immeasurable.

In a Preface to the third (revised) English edition, Freud himself said of his seminal work—which, he observes, ‘‘surprised the world’’—that it represents ‘‘the most valuable of all the discoveries it has been my good fortune to make,’’ adding that ‘‘insight such as this falls to one’s lot but once in a lifetime.’’

Initial Reception Freud was gravely disappointed by the initial reception of The Interpretation of Dreams, which was, according to Ritchie Robertson in an introduction to the 1999 translation, ‘‘muted but respectful’’; it sold only 350 copies in the first six years of publication. However, as Freud’s reputation as the founder of psychoanalysis grew throughout the first decade of the century, a second printing was called for (1909), and a third was in demand within a year. Over the next ten years, he revised the book for eight different editions, adding a preface with each new printing.

Criticism and Controversy Freudian theory, though highly influential and much celebrated during Freud’s lifetime, was, from its inception, controversial and subject to extensive criticism. Since his death, psychoanalytic theory has been attacked on many fronts. In 1953, Nathaniel Kleitman discovered the phenomenon of rapid eye-movement (REM) during the dream state of sleep. This and subsequent neurological and sleep-lab research over the past half-century have led many to conclude that Freud was wrong in most, if not all, of his theories of dream analysis. Feminist theory, as early as the 1950s, attacked Freudian theory for being gender biased and having a disastrous effect on societal attitudes toward women. In the interior of Freud’s study, including the famous couch where he treated patients addition, the development and increasing use of drugs to treat depression and other psychological disorders has tended to throw psychoanalysis as an effective method of treatment into a dubious light.

Freud’s Legacy Peter Gay, author of the much-celebrated biography Freud: A Life for Our Times (1988), has made the oft-repeated assessment that ‘‘today we all speak Freud,’’ meaning, ‘‘his ideas—or ideas that can be traced, sometimes circuitously, back to him—have permeated the language.’’ In a 1999 article in Time magazine, Gay quotes the poet W. H. Auden, who, upon Freud’s death in 1939, stated, ‘‘If often he was wrong and, at times, absurd, to us he is no more a person now but a whole climate of opinion.’’ Gay goes on to assert that although Freud remains controversial, ‘‘on one thing the contending parties agree: for good or ill, Sigmund Freud, more than any other explorer of the psyche, has shaped the mind of the 20th century.’’ He adds, ‘‘The very fierceness and persistence of his detractors are a wry tribute to the staying power of Freud’s ideas.’’

A 1989 article in Psychology Today , marking the fiftieth anniversary of Freud’s death, includes comments from leading psychologists concerning Freud’s legacy to the twentieth century. Though he remains highly controversial within the profession, ‘‘Most agree that we owe a great deal to Freud.’’ Jerome L. Singer describes Freud’s legacy as that of ‘‘a lifelong exploration that has stirred the imagination of thousands of thinkers in this century.’’ Will Gaylyn concurs that Freud ‘‘has influenced our language, perceptions and institutions more than anyone else in the twentieth century.’’ Robert Jay Lifton similarly considers Freud ‘‘a great figure who was responsible for one of the great intellectual breakthroughs in...