By Matthew Gurewitsch

In the Hollywood Hills

If ever a man's home was his castle, here it is: a curiously monastic, modernist citadel magically suspended atop Benedict Canyon. Blowing down from the desert, the winds notorious in local lore as the Santa Anas have swept the chronic Los Angeles smog beyond the horizon. Over a panorama that stretches from the cut-glass towers downtown clear to Catalina Island, some 50 miles off, hangs a sky of blue crystal, deepening with the sunset.

"You've chosen the perfect day," James F. Goldstein advises a visitor who has come just for a look at a petite new pavilion of molded concrete, 350 feet square, completed last summer: a very rich man's caprice. A structure of surprising grace in its own right, it is in fact but a shell. The treasure that lies within is an installation by James Turrell, an artist whose canvas is the viewer's perception and whose paint is light. One of the so-called "light and space" gang who emerged in the 1960s, Mr. Turrell makes nothing like art objects as that term is usually understood. His structures -- "empty" chambers or tunnels, raised ceilings, windows in blank walls -- function as frames for views that behave in highly unexpected ways. Under Mr. Turrell's spell, the eye will read infinity as the exact distance to the wall of a little room or a hole as a solid surface. Yet so subtly does he wield his power that for a long time the viewer may think he is "seeing" nothing at all.

Entering James Turrell's Sky Space, the visitor notices the cornerless, pristine walls, on which a light show plays out, accentuated by the darkening sky that peeks through the boxes on the ceiling and on the gentle curve of the wall. Experiencing it can be mystical.

The Holy Grail for devotees of Mr. Turrell's elusive art lies several hundred miles to our east. It is Roden Crater, the cinder cone of an extinct volcano in Northern Arizona, the rim of which approximates a perfect circle. Work on the project began in the 1970s, and when it is completed, that circle will be perfect. Thanks to the phenomenon known as celestial vaulting, the sky will then appear to rest as a miniature dome on the crater, a perfectly fitted simulacrum of heaven. Mr. Goldstein dreams of visiting Roden Crater, but makes the pilgrimage to his own Turrell chapel twice a day.

Reportedly the son of a department-store owner in Milwaukee, and reputed to have made a billion-dollar fortune by developing Century City on Santa Monica Boulevard, Mr. Goldstein revels in his reputation as a basketball fan and clothes horse, dressing in cowboy couture as reinvented by such guerrilla designers as Claude Montana, Jean Paul Gaultier, John Galliano, and Roberto Cavalli. His hair, gray and crinkly, falls nearly to his shoulders. His eyes, light blue, give off a boyish sparkle. His speech is soft, touched now and then with hints of shy braggadocio. He declines to give his age.

Before leading the way to the Turrell -- known variously as "Above Horizon," "Sky Space" or "Sky Box" -- Mr. Goldstein conducts a full tour of his astonishing fief. He discovered the property in 1972, while shopping for his first house. Life in high-rise apartments, he explains, was hard on his Afghan hound, Natasha. Smitten from boyhood with the architecture of Frank Lloyd Wright, he responded instantly to the daring conception of John Lautner, a Wright disciple and California legend. True, the house -- then 10 years old -- was the sad shadow of what it should have been: built on the cheap, demeaned by green-shag carpeting and paint jobs to match. Nevertheless, Mr. Goldstein knew his quest was at an end.

Since claiming his mountaintop, the new owner has been inching it toward Platonic perfection. (Natasha, who loved her new home, has never replaced.) For the past 20 years, Mr. Goldstein says, construction on the grounds has proceeded on a daily basis. He has upgraded the whole in ways both minute (adding a custom-designed ashtray) and monumental (adding vast expanses of plate glass). As adjacent parcels have become available, Mr. Goldstein has snapped them up.

Behind the sleek Modernist steel gate to his driveway (think Chrysler Building) lies a domain that measures some three acres -- converted, by the landscape designer Eric Nagelmann of Santa Barbara, into a lavish tropical jungle. Though better built and maintained, the zigzag path down to the Turrell recalls the trails of the Napali Coast, halfway across the Pacific.

The inspiration to nestle a sky box halfway down his private cliff came to Mr. Goldstein some 15 years ago, when he visited someone else's, one of two dozen or so Mr. Turrell has built around the world. Mr. Goldstein remembers that it was somewhere out there in the urban sprawl but forgets who owned it or exactly where it was. Just what it was about the experience that stayed with him, he does not say. The simplest explanation may be that he buys what he likes. He can afford to, as his wardrobe attests.

Throwing open the sanctum, Mr. Goldstein reveals a concrete floor that seems to float in midair and pristine walls without corners, flowing smoothly into an equally pristine ceiling, the whole bathed in perfectly even ruby light. Dazzled, the visitor assumes the viewing position: reclining on a sunken leather pad. At the touch of a remote, Mr. Goldstein activates an overhead panel that retracts like a sunroof. Other sky boxes have just one such aperture. Mr. Goldstein suggested another, and Mr. Turrell gave him one, off center to the left. At a further touch of the remote, a second panel disappears, this one a rectangle cut where the wall gently curves.

As the illumination cycles from blood red to lime green to peacock blue and silver through royal purple and white, the darkening sky fuses with the wall, mutating from powder pink through slate blue to a spectrum of ravishing grays, dove to gun metal. Instantly, the mind is flooded by tranquillity, yet the experience is by no means soporific. The senses feel razor-sharp, in a state of perfect readiness. What mystics call enlightenment or ecstasy must be very like this.

Like the second aperture in the wall, the prismatic washes represent an advance on the earlier sky boxes. "When I ordered the lighting system," Mr. Goldstein says, "it only came in single colors. But there were production delays, and in the meantime they came out with new technology. I was lucky." Evidently, Mr. Turrell likes the new technology, too. As revealed by a recent -- very public and popular -- installation at the Museum of Fine Arts, Houston, he is extending his palette.

Back on his feet, the visitor cannot resist an impulse to examine the recessed light bulbs, which prove to be scarcely longer than a fingernail and little thicker than the cartridge of a mechanical pencil. "Look out the window before you go," Mr. Goldstein says. There lies Los Angeles, like a sea of starlight.

Under cover of nightfall, climbing back to reality, I have to ask. "What did it cost?" Mr. Goldstein echoes with the smile of a lonely pharaoh. "I don't like to keep track myself. Without calculating, and I haven't, I do know it's above a million dollars. I have no regrets."