Susan Rothenberg at 48 is a painter of the rarest sort, an art star beyond fashion.

Her pictures have been shown at the Venice Biennale, at the Museum of Modern Art, at the Tate Gallery in London. Her portrait has appeared in Vanity Fair and Vogue, and she's married to an art star, the conceptualist Bruce Nauman, and all her pictures sell. And yet her art has in it no shimmer of the voguish. It is neither chic nor pretty. Her touring retrospective, now at the Hirshhorn Museum and Sculpture Garden, explicates no theories. It has no political agenda. It does not lean on slogans, photographs or texts, nor does Rothenberg devise room-devouring installations. What she does is paint.

It is what she paints that strikes one -- like a blow against the chest. For dwelling in her pictures are strange totemic presences, bones and boneless beings and horses without eyes, which are not hers alone, which belong to us as well. They promise us no pleasure, they offer no direction, and yet they feel, while alien, intimately ours, like unbidden visitations coughed up from within.

A stolid, pale horse came first, in 1974. Its neck is thick, its stance is tense, its hue is pinkish gray. That little pregnant image -- almost casually sketched on a square of fraying canvas -- initiates this show. Rothenberg -- a native of Buffalo who studied at Cornell and then very briefly at the Corcoran -- was painting in New York when that ghostly horse appeared. She was a minimalist of sorts then, as were a thousand other painters, but her minimalism was different. The fields in her paintings have never had the emptiness, the uninflected smoothness of most wholly abstract art. Instead they had about them then, and have about them still, something shivery and sensitive, as if they were alive.

Her restless seeking brush somehow conjures into being a fog of fluctuating light -- like the image that is seen against the inside of your eyelids. It's as if she has depicted a kind of mental space that's anxiously awaiting a visual idea. Looking at her pictures, one knows what people mean when they speak of "fields of thought."

That horse looked like a wordless thought -- something new to urban abstract painting yet old as art itself.

One of the chief monuments of prehistoric art is the so-called Vogleherd horse, a graceful little pony carefully carved out of mammoth tusk 30,000 years ago. And just think of its descendants, from Pegasus to Trigger -- there's the unicorn of innocence, the steed that bears the hero, the horses of Apollo that pull the chariot of the sun. Horses carry darkness too: the nags of the Apocalypse, the nightmares of decay.

All that vast symbolic weight is there, by implication, in the horse that Susan Rothenberg sketched without much thinking -- she was really only doodling -- in 1974. Yet she must have known its power the moment it appeared. That image, and its progeny, held her many years, and somehow freed her work of faddishness, for the colors she preferred -- those earthy terra cottas, those sooty blacks and ashlike grays -- somehow drove her horses deep into dream time, the time of not-yet-quite-asleep, of animals that speak, of oil lamps in caves.

Her horse might have remained a practical device, an antidote to purely formalist abstraction, but soon it started stirring with a power of its own. As you proceed through her show, you can see that creature twin itself. It stumbles, then it gallops, then it flies to pieces. By the time its eyeless face goes a sudden startling blue, it's already half a person, like some moving presence glimpsed in a clouded mirror. Its legs become embracing arms, its face a kind of devil's mask, and then its flesh dissolves until little more is left of the horse that she began with than a single floating bone.

Rothenberg, right from the start, knew how to activate a surface, vitalize a drawing, and make a canvas dominate the wall, but what one remembers most -- what sends chills down the spine -- is her receptivity to her metamorphosing vision.

"Three visions have I seen," wrote Yeats, "the worst of these a coat upon a coathanger." In re-imagining familiar things -- a thick-hooved lumbering horse, a tuning-fork, a bone, a hand against an outlined head -- Rothenberg can see, and make us see as well, that such things contain ghosts.

Sometimes she can lose us. Her bile-spewing eyeless heads of 1978 veer too close to cartoon. A peculiar male figure, slender-headed, spectacled and gaunt -- "Mondrian," she called him -- that began appearing in her paintings in 1984 (shown here at the Phillips in 1985) has remained closed, for the most part, to the viewer's understanding. But when she hits an image right, as she has done again of late, she can make the viewer gasp.

There's a figure in her "Blue U-Turn" (1989) that's part mermaid and part male and wholly unforgettable. It's like a painted image of the swerving of emotion. And, in the painting she calls "Orange Break" (1989-90), lips turn into knees; it's an image that's part act of love, part whisper, part devourment, part kiss.

No cunning artist's strategy, no well-devised career path is revealed in this show. Instead, one tends to see the painter sitting there, waiting, sketching and rejecting, and waiting yet again for a vision to appear. "All the horses started out on the backs of envelopes," says Rothenberg in an interview in the catalogue, "or any scrap of paper lying around. The first paper that came to hand was usually in the mail pile. Rather than getting a sheet of paper and putting it on the wall and developing a drawing, I'd just sit in my chair and say, 'What if it was like this?' ... Little doodles on and on."

Time and time again the viewer is reminded of the role played by the medium, vulnerable, entranced, by the summoner of spirits in the conjuring of art.

The Rothenberg show presents us with a painter of unquestionable integrity. In a time of insecurities -- when hectoring ideologies, shiny blown-up photographs, texts and wan reflections of the so-called "media world" -- litter the horizon, Rothenberg's career is deeply reassuring. This moving exhibition, with its emotional intensity, its questing for essentials, its 20 years of straight-on work, lets us feel again the power, the conviction, that can still be conveyed by handmade works of art.

"Susan Rothenberg: Paintings and Drawings" is at the Hirshhorn until May 9, after which it will travel to St. Louis, Chicago and Seattle.