Perhaps the oddest item on display at the National Museum of American Art is Throne of the Third Heaven of the Nations Millennium General Assembly. This gleaming assemblage of foil, colored paper, and plastic was constructed in the ’50s and ’60s by folk artist James Hampton, who intended it to announce the Last Judgment. Hampton’s belief system may have been offbeat, but many artists follow similar creative urges, says curator and teacher John Beardsley, author of Gardens of Revelation: Environments by Visionary Artists (Abbeville Press). Beardsley, who works from a Dupont Circle office when he’s not on the road, has traveled all over the world seeking landscapes made by “extreme individualists”; he cites the Watts Towers in L.A., a virtual cathedral of ceramic and glass shards built by Italian immigrant Sam Rodia, as the quintessential example of untutored art. “People look at this stuff and think that it’s a form of crazy behavior, but in a way I think it’s just the opposite,” Beardsley explains. “Most of these people have nothing—some are extremely disadvantaged—but they pick up a stone or a plate and use it as a metaphor for making something of their lives. That to me is a poignant expression of mental health.” Gardens of Revelation, a coffee-table book that balances color photos and exhaustive analyses of major works, documents artists from R.E.M.-friendly Howard Finster to Ferdinand Cheval, the baker/postal worker who carved porous limestone chunks to build the Palais Idéal in Hauterives, France. “The appeals are multiple,” Beardsley says. “There’s a kind of vigor and spontaneity that’s missing from a lot of the more calculated or contrived kind of art…and I’m also drawn to the fact that these people are articulating personal philosophies.” He doesn’t agree with most of those philosophies, he admits (“Some of them I find a little reprehensible—they have some negative opinions about women or immigrants”), but he respects the artists for making public audiences consider “how we define ourselves as individuals, and to what extent we conform to community standards.”