Robert Irwin isn’t taking anything for granted. The eighty-seven-year-old artist is up early on a Monday morning to oversee a team of workers hustling to get his installation at the Chinati Foundation, in Marfa, ready for its debut. Overhead, the West Texas sky hangs brilliantly blue, a dramatic change from the hail and streaky grays of the evening before. “Hopefully that’s going to be my main event,” Irwin says, gesturing upward. “You can’t beat it. It’s the best show in town.”

Built on the site of the demolished hospital at Fort D. A. Russell, Irwin’s as-yet-untitled work blends the disciplines of architecture, sculpture, and landscaping. The center of the project, an illuminative rebuild of the original hospital, is, like all of Irwin’s work from the past 35 years, engineered to draw viewers into a deeper experience of their physical surroundings. Due to open on July 23, the project differs from Irwin’s other work primarily in its permanence and monumental scale. If successful, it will likely be seen as his defining achievement.

That’s a heavy burden of expectations for an artist most famous for working in the ethereal language of air and light. Irwin is feeling apprehensive, though his jitters conceal a profound confidence in his philosophy and methods. “We’ll see whether it’s art or not,” he jokes, rattling ice cubes in the cup of Coca-Cola he always keeps on hand. “I would say it might be a split decision for a lot of people—if you’re looking for something, it’s going to appear that there’s really nothing much there. To be slightly poetic about it, I’m trying to grab a will-o’-the-wisp. If I grab it too hard, the thing’s laborious. If I don’t grab it hard enough, it doesn’t happen.” Irwin’s choice of metaphor is appropriate in a town where, every night, folks gather on the side of a nearby highway to catch a glimpse of mysterious floating lights that may be a supernatural phenomenon or a case of mass delusion.

For years, Irwin has been obsessively involved in shaping every detail of the project, from the type of glass in the windows to the irrigation of the exterior grass to the mining of the volcanic basalt that is part of his courtyard sculpture. As we speak, he’s preparing for the arrival of a set of scrims, which will run down the corridors of the C-shaped building, transforming the quality of the light coming through the windows. Unlike Irwin’s other permanent building project, the Dia:Beacon museum, in New York’s Hudson River Valley, this site isn’t designed to house or contain art. Instead the building and grounds are the art.

To the experienced museumgoer—or anyone else, actually—the building’s long corridors may appear empty, with nothing but bare windows where wall hangings ought to be. Irwin would counter that, in fact, the site is full to overflowing—with light, with landscape, with history. “All these things I’m doing are the best I can do to make sense out of being in Marfa,” he says. There’s a feeling of excitement and possibility in the area, he insists, that can’t be put into words. It’s a physical sensation, and hence, malleable by an artist’s subtle hand.

“There’s something about being here,” he says. “You’re driving down I-10, and it’s kind of dull. Then the minute you hit Van Horn and turn right and start to drop down, the whole thing changes, and it’s kind of magical. It stands up and hums.” The entire project is an enormous bottle for catching the lightning of this miraculous West Texas feeling.

Irwin, who has lived in San Diego for the past quarter century, is one of the last giants standing from a generation of artists who, in the early seventies, sought to bring the practice of visual art out of the studio, gallery, and museum and into the world. Many from this cohort developed deep relationships with Texas and the American Southwest. Most famously, Donald Judd came to Marfa and transformed it into an international art mecca, drawing crowds to his minimalist box sculptures, which became the heart of the Chinati Foundation’s collection. Around the same time, the Panhandle caught land art fever, sprouting a collection of outdoor works like Robert Smithson’s Amarillo Ramp. Michael Heizer, James Turrell, and Walter De Maria made their marks in Nevada, Arizona, and New Mexico, respectively. Irwin is, in a sense, the last of the gang to arrive.

The story of how these artists found the means to create their often massive undertakings is also a Texas story—which is to say, a story of eccentric dreams and oil-boom-and-bust fortunes. Like many Texas art stories, it begins with John and Dominique de Menil, heirs to the Schlumberger oil-field-services fortune, who relocated from Paris to Houston after the Nazis occupied France, in 1940. When a friend criticized them for moving to the “cultural desert” of Texas, John is reputed to have said, “It’s in the desert that miracles happen.”

That quote echoes a favorite line of Irwin’s, which he attributes to the modernist painter Kazimir Malevich. As Irwin tells it, Malevich’s artist friends were complaining about the painter’s empty-seeming white-on-white canvases. “You’ve left us with a desert!” they told him. “Yes,” Malevich replied, “but it’s a desert of pure feeling!”

The Menils brought to Houston an appreciation for the kind of art Malevich spoke of, sculptures and canvases that dispense with the pictorial tradition in favor of effects that take place in the viewer’s mind and body. Perhaps this taste is most apparent in Houston’s Rothko Chapel, a house of worship filled with a series of black-on-black canvases—blank-seeming to some, freighted with religious depth to others.

But it was the Menils’ daughter, Philippa, who really opened the frontier to the colonization of New York artists. The Dia Art Foundation, co-founded in 1974 by Philippa, spent enormous sums to allow artists to create work that engaged the natural world, such as Judd’s Marfa boxes. Around the same time, Amarillo oil heir Stanley Marsh 3 got into the game too, sponsoring Smithson’s Amarillo Ramp and kitschier projects like Cadillac Ranch and Floating Mesa. For the American West, the seventies were the proverbial desert rainstorm that comes along rarely but leaves the landscape magically transformed—abloom, in this case, with modern art.

The land art boom ended with the oil glut of the early eighties, in part because the Menil family cut off Philippa’s access to her rapidly dwindling inheritance. Judd, however, used legal threats to wrangle promised assets and money out of Dia and set up the Chinati Foundation. In a sense, the Menil legacy is underwriting Irwin’s work in Marfa even today.

Partly out of environmental concerns, the reputation of these landscape-altering works has suffered over the intervening decades, with practitioners like Heizer written off, in the words of one academic, as “bad boys with bulldozers.” Still, the art world’s desert sojourn broadened the possibilities of artistic expression in ways that continue to matter today.

There are few places in the world where audiences are confronted with works of art in dialogue with their natural surroundings, through the cycles of day and night, the seasons, and the passage of decades. These special places force new generations to question the ideal of the artwork as a product that can be bought and sold and moved from place to place. They also suggest a different way of experiencing beauty—not captured in a frame, insulated from context, and guarded behind ropes but alive to the ways of the world, drawing depth and meaning precisely from that contingency.

Looking back on the seventies, Irwin is skeptical of the traces his peers have left on Texas and the interior West. He dismisses land art as a flawed philosophy. “They’re grabbing the subject by the wrong end,” he says, calling Amarillo Ramp, for instance, a “painting on the ground.” Smithson used the land as a canvas upon which to draw enormous geometric figures; Irwin reverses that logic, erecting his hospital building as a blank canvas against which the natural surroundings can be experienced in compelling relief.

Irwin doesn’t mind the association with Judd, who he says was “the closest to somebody who had the same interests as me.” But it’s hard to imagine Irwin buying up a former Air Force base, as Judd did, and establishing a foundation to present his works in perpetuity. Irwin’s modus operandi is humbler than that—one reason, probably, that he has never made an installation of this scale until now.

Irwin’s post-1970 output can mostly be divided into three categories: ephemeral you-had-to-be-there temporary installations, design work for buildings and grounds that showcase the work of other artists or architects, and abandoned plans for more-ambitious projects. For a while, it seemed as though his Marfa work was destined for the final grouping. The undertaking dates back to 1999, when Chinati first extended an invitation to Irwin. He spent years trying to design a project that utilized the original hospital building, until concerns about structural instability forced Chinati to raze it, compelling him to start from scratch. In 2006 Chinati put up a show of his various plans for the site. The exhibition filled two buildings.

Somehow, however, the institution and artist buckled down, found common ground, and got the project to the finish line—they hope. “When you work with Bob, there is a bit of a leap of faith,” says Chinati director Jenny Moore. “The blueprints or the plans are one thing, but the very nature of his work is that it changes and develops over time. He responds to conditions. So while the design of this project was finalized in 2013, there have been so many interesting developments since then, and a few I’d anticipate happening in the next month or so, when Bob finishes the piece. You follow where the artist leads.”

Clearly, Irwin is well served by Chinati’s commitment, inherited from Dia and the Menils, of offering artists permanent spaces to create work meant to stand the test of time. Still, asked to reflect on the task of making permanent work, Irwin, approaching the end of his ninth decade on earth, scoffs. “There’s no such thing as permanence,” he says. “Everything is changing all the time. The quality of the light isn’t permanent. The environment around it changes. How you enter, where you come from, why you come, all those things are continuously changing. That’s, to me, the life of the thing.”

Unlike so many of his peers who came to these longitudes in the seventies and eighties, Irwin seems unconcerned with leaving a personal legacy here. “We like the idea that we leave something after ourselves. That’s a sentiment that everybody has in some way or another,” he says, as another storm begins to roll in overhead. “But it’s an illusion.”

If his work in Marfa has a lasting impact, he says, it will be in the hearts and minds of those who visit here, and in the imperceptibly altered values of a society where art, like the natural world, has become something we take for granted as just another consumer good. It’s not the sort of impact anyone can measure, but trust Irwin to sense it if it’s there.

“What would I want to get out of this thing?” he asks, extending his palm to indicate perhaps his project site, perhaps West Texas, or perhaps the world at large. “To make you feel that this is really a place worth taking care of. It’s beautiful, it’s wonderful, it’s enlightening, it’s thrilling—whatever word you want to put on it. No one else takes that role but artists. That is what is unique to art.”