Some avant-garde artists stare you down; Robert Wilson enfolds you. His work is full of mysteries, but maybe the greatest one is how he can be so hermetic and yet so accessible. Wilson's densely symbolic staging is above all welcoming. His images invite associations, response, sidetracks. He's not a lecturer, he's not even a guide -- he's a partner. He wants to whirl you out on the mental dance floor. He wants you to dream along.

Probably the American director with the greatest international reputation, Wilson creates long, elaborately designed productions -- of opera, of the classics, of his own ideas -- so expensive to mount that they usually turn up in only a couple of places for a short time. Washington audiences haven't had him in town since "The Knee Plays" five years ago. Robert Brustein's American Repertory Theatre in Cambridge, which has so often given Wilson a home, is now producing his version of Henrik Ibsen's last play, "When We Dead Awaken." For theater lovers, it's the stuff that dreams are made of.

"When We Dead Awaken" opens with a scene in the garden of a mountain spa where Rubek, the world-famous sculptor, and his young bride, Maya, sit discussing their return to their native Norway, their faltering relationship, his restless dissatisfaction with life. Wilson puts them in two amazing, rather frightening chairs -- tall gray metal things with slatted backs. Rubek and Maya might be sitting in window seats with Venetian blinds behind them, indoors rather than out, isolated from each other. The chairs also suggest skyscrapers, the man-made mountains that represent a supposed triumph over nature. Then it turns out that they move, with a hideous grinding sound: They're also incomprehensible machines. Ibsen's theme of alienation from the true self -- of "death" -- is undergirded by Wilson's images of industrial society's separation from nature, another rendering of the same type of alienated "death."

Wilson just keeps on doing this, providing images that complement Ibsen without mimicking him: shadows, echoes, deepening hues. He works very cleanly and simply, without fuss, even with a hint of playfulness. He suggests Ibsen's mountains with isolated rocks. For a stream he spills blue light across the stage. All he shows of an old hunting lodge is a collapsed, blackened doorway that, in its ruin, suggests a Japanese gate, and that leads nowhere. His mountain peaks and forests are as haunted as a landscape out of the Brothers Grimm.

This is entirely appropriate for a playwright who once wrote a drama called "Ghosts." Ibsen was a mystic and poet who often wore the sensible shoes of realism. In "When We Dead Awaken" he ran wild and barefoot. The play is set among those Norwegian mountains where, in his earlier "Peer Gynt," trolls ruled. The troll here might seem to be the animal-like hunter Ulfheim, who sets his sites on Maya. But the true troll-soul is Rubek's, shriveled with guilt over Irene, the model whose love he devoured for the sake of art. Rubek is dead, unable to create. When Irene, now mad, reenters his life, he determines to try to live once more. With its crossed pairs of lovers meeting in a mountain forest, "When We Dead Awaken" sometimes suggests a grim "Midsummer Night's Dream." That play ends with lovers united; Ibsen's ends with Rubek and Irene united in death. With a fine disdain for the niceties of realistic theater, Ibsen destroys them with an avalanche.

"When We Dead Awaken" is actually a ghost of Ibsen's last masterpiece, "The Master Builder." In that play, the artist is not a sculptor but an architect who has created great buildings but caused the accidental death of his children. In the end, he is pushed to self-destruction by the hero worship of a young woman. In "When We Dead Awaken," the artist, Rubek, is married to a young woman but has tired of her. His shunned ex-model, Irene, loves children but has none: She calls Rubek's statue of her -- made of white marble, like a tombstone -- their "child." This time Ibsen's hero turns from the younger woman to the older in order to find new life, but here, as in "The Master Builder," he pays with his death. Ibsen isn't as hard on Rubek as he is on the artist-figure Lovberg in "Hedda Gabbler," whom he shoots in the belly in a whorehouse. But he's still an anti-romantic, denying even the protagonist who represents his own artist-self any transcendence, burying him in ice.

"When We Dead Awaken" is more suggestive than dramatic. Ibsen may have died before doing a final draft -- the play has a bumpy, awkward quality unlike any of his other work. This is, of course, what makes it perfect for Wilson. If "When We Dead Awaken" can be seen as Ibsen's nightmare of "The Master Builder," then Wilson's production is his dream of "When We Dead Awaken," as if he nodded off while brooding over the text. We glide through the play on his sleeping thoughts.

It's a postmodernist commonplace to provide directorial glosses to a text and present them as if they were the play itself. Those who attended Peter Sellars's productions at the Kennedy Center got a taste of this. Sellars could create astounding images, but basically his work added up to a series of Harvard-brat footnotes to theater history. Wilson directs for an educated audience -- you miss a certain level of revelation and pleasure if you don't have some familiarity, for example, with Munch's paintings and Japanese woodblock prints. But Wilson doesn't rely on these references -- they remain just the gloss. "The question," Humpty Dumpty said to Alice, speaking of language, "is which is to be master?" Postmodernism is itself a language, a series of signs now hardening into cliches -- and Wilson is its master. The point of his relationship to postmodernism isn't that he brilliantly fulfills its tenets; the point is that postmodernism allows him to use reference and deconstruction to achieve art.

Under Wilson's direction, as the characters talk they make movements and adopt poses that seem to spring from what they are feeling or thinking rather than what they are saying. This deliberate artificial formalism suggests Japanese drama, but there the movement is in direct support of the text. Here it's a companion to the words' meaning, a deepening, a shadow. And it isn't meant to subvert our understanding -- it's not a scornful lecture about how little we comprehend reality. It's an invitation to sink down through the play's levels of meaning. Against Wilson's mountain backdrops -- the skies the elusive gray-blue-white of Japanese prints -- the characters move continually from one evocative stage pattern to another. Some of them give you a jolt of recognition; some are familiar but fleeting and ungraspable, like a fading dream.

With all his visual skill, Wilson is most audacious and effective in his use of sound, the wraparound "environments" designed for him by Hans Peter Kuhn. Having sound come at you from all directions is something you can get in a movie theater; it's Wilson's use of the technique that is so extraordinary. At the beginning of the play, Maya and Rubek are complaining about the silence so intense you can almost hear it. This being a Wilson production, you do hear it -- a gigantic, rushing sound. You think it's the wind, then you think maybe thunder, then it sounds like the sea, but it can't be because you're in the mountains. Not until the play's end do you realize it was an avalanche.

Wilson also mikes his actors and sends their voices all over the theater. This splits the text from the movement even more decisively and gives the production its distinctive double cadence: What you see is moving to one rhythm, what you hear to another. Again, the divided parts of the experience enhance rather than fight each other. You get the story on two levels, almost at two difference speeds. It's like the state before sleep where you're still aware of noises in the room but your mind is spiraling out toward dreams. Wilson achieves the grail of postmodern theater: Emphasizing the separation of audience and play, he draws both into cooperation. His production becomes, almost unbelievably, an illustration of the workings of human consciousness and perception, an aesthetic CAT-scan pattern.

Where does this leave Ibsen? By choosing such a misshapen, partially surreal, perhaps unfinished play, Wilson has guaranteed himself an enormous amount of leeway. "When We Dead Awaken" is a text that's easier to enrich than to violate, and the opacity of its ultimate meaning fits right in with Wilson's statement that he doesn't want to understand what he presents, that he wants to give the audience as much interpretive freedom as possible.

This sounds good, and Wilson makes it work to an impressive degree. Still, any choice a director makes about a play is an interpretation. Wilson is working with a lively, flexible translation by Robert Brustein (a welcome change from the usual stodgy Anglicized Ibsen) and has accepted, or suggested, Brustein's cuts. Sometimes these are merely practical, the sort of thing a translator-producer has to do when his director decides to combine two of Ibsen's characters (Irene and her nurse-companion) into one. Sometimes they eliminate a point Ibsen went out of his way to make. Ibsen has Irene tell Rubek that he promised to take her to the heights and show her "all the glory of the world," but that when she got to the heights she fell to her knees and worshiped him. Brustein and Wilson leave out the worshiping line, and her subsequent metaphorical-mystical vision of a sunrise, something Ibsen has established that Rubek has never seen. If Ibsen made the point, why didn't they?

Postmodernism's credo that the text is no more "important" than those -- director, audience -- who "encounter" it comes very near to leaving the dry safety of theory and falling into the mud of human weaknesses like arrogance and cowardice. Wilson is brilliant. Directors not so brilliant can subvert a text not in order to extend it but just to pamper their egos or indulge their laziness.

Wilson, however, shows how far a brilliant director can stretch a text and still fulfill it. Between acts, he has the great black tap dancer Charles "Honi" Coles perform songs and lead movement. Lean and dapper in a three-piece white suit and shoes, gray socks and a silver tie, Coles is almost impossibly handsome. As a dancer, he was once as loose and graceful as flowing water; for anyone who ever saw him perform, it's a terrible moment when he comes onto the stage stiff-legged and limping slightly. But Coles lame moves more elegantly than most healthy people in their prime, and he still sings with the clear sweet voice of a boy. He wrote the songs himself. They're about the folly of love looked back at from old age. Watching this old master sing about his heartache, in between acts of a play by an old master on the verge of death that is about an old master trying to love again, is almost overwhelming. When Wilson is directing at this height of complexity and wonder, he takes you up on the mountain all right -- and unlike Rubek, he delivers glory.

Whatever their arguments throughout the evening, Ibsen and Wilson meet at that final avalanche -- a crazy, absurd thing to try to make happen onstage, an act of theater madness. Wilson gives Ibsen his avalanche: The roar fills your head, and Rubek and Irene sink beneath the ice. And then everything is still and silent. Snow falls noiselessly from the flyspace down onto the set. It's the emptiest stage I've ever seen. "When We Dead Awaken" isn't a perfect production, but who needs perfection when you can have greatness? Robert Wilson is a dream lover.