This year marks the 60th anniversary of the founding, in Paris, by the modernist painter-sculptor Jean Dubuffet, surrealist leader André Breton, art critic Michel Tapié and others of the Compagnie de l’Art Brut, a non-profit association dedicated to the investigation and promotion of a kind of art that had nothing to do with the work honored by regular museums or with academic art history.

Instead, the creations that seized the attention of Dubuffet and his colleagues had been made by isolated, self-taught, sometimes visionary artists who lived and worked outside mainstream cultural traditions; some had been patients in psychiatric hospitals. Dubuffet called what they produced art brut ("raw art") and published a journal and presented exhibitions that explored their unusual art forms. Such works by "outsider artists," as they came to be known, included drawings by the Swiss artists Adolf Wölfli and Aloïse Corbaz and paintings by Joseph Crépin, a French plumber. Their artworks were sui generis, answerable, in aesthetic terms, only to themselves. Often they were characterized by techniques or formal aspects that had never been seen before, even in the experimental modern art of the early post–World War II period.

In his own art-making, Dubuffet would also be inspired by such indigenous forms of expression as graffiti, but he probably never could have imagined the depth of appreciation that would later evolve for, as he put it, the "works produced by persons unscathed by artistic culture" that he passionately championed. Today, the sale of outsider or self-taught artists’ works (the terms are often used synonymously) has become a recognized sector of the art market. Supporting it are countless books, exhibitions and catalogs, magazines like the London-based Raw Vision, galleries and specialized museums.

One of the most important of these museums is the Collection de l’Art Brut in Lausanne, Switzerland. Opened in 1976, whose core holdings came from Dubuffet’s own collection. Others include the American Visionary Art Museum, in Baltimore, and Intuit: The Center for Intuitive and Outsider Art, in Chicago. In New York, the American Folk Art Museum focuses part of its programming on the work of self-taught artists, which, technically, is not folkloric at all, as it does not replicate or reinterpret well-established, vernacular forms. Galleries specializing in self-taught art can be found in France, Germany, Britain, Canada, the United States and other countries. A relatively new venue in Japan is Yukiko Koide Presents, in Tokyo, which calls attention to self-taught artists from East Asia.

As the outsider/self-taught field has grown, certain long-simmering issues and new developments within it have challenged the thinking of its devotees. For example, as an increasing number of collectors, critics, curators and artists learn to love the kinds of unpredictable work they encounter in this field, for some, the long-standing aesthetic divide between outsider/self-taught and good modern or contemporary art—or any kind of art—is dissolving. What’s good and interesting is valuable no matter where it comes from, they believe. Some find more originality, inventiveness and soul in the works of self-taught artists than they do in what the Boston collector Jay Davidson, after visiting last year’s Venice Biennale, called the "overly planned, pretentious monuments to self-aggrandizement" that abound on the contemporary art scene.

Meanwhile, some outsider-art insiders are starting to wonder: Should there even be a separately designated "field" at all for this kind of art? Never mind that many of its aficionados are still debating just what to call it; "outsider," "self-taught," "non-academic," "intuitive" and "visionary" are all terms that have been used to describe it, but no one label adequately applies. Outsider art lovers are still defining this kind of work, too. After all, today, some of the basic art-making conditions Dubuffet had cited in defining outsider artists no longer exist. Today, for instance, almost no one is ever too far away from such culture conveyors as radios, TVs, mobile phones or Coca-Cola, so what does it mean to be "isolated from culture"?

Randall Morris, of Cavin-Morris Gallery in New York, a well-known outsider/self-taught art venue, notes, "The field has shifted and will continue to shift. The old labels need to be constantly re-evaluated. What holds us together as a field is that we have chosen to specialize in one aspect of the art world at large." Even so, Morris also shows antique textiles from Japan, African sculptural objects and other so-called ethnographic art forms. Morris does not necessarily embrace the outsider label—his own fascination is with the universal appeal and spiritual aura of the most powerful artistic creations, whatever their origins—but he realizes that the marketplace already uses the term.