KANSAS CITY, Mo. Over the years, retired lawyer Tom Baker had done a lot of business with Jim Santilli, owner of Kansas City Upholstery. But the phone call Baker received from his friend in early July had nothing to do with furniture.

"There's this artist I'm exhibiting," Santilli told Baker, "and she says there's a piece of her work hidden behind a mirror in your building."

Baker told Santilli, "Come show me."

A few days later, Santilli arrived with a newspaper clipping from 1957 that showed a mosaic-covered wall with two elevators set into it in the Regency House on the Country Club Plaza.

The two men stood in the north lobby, where a mirrored wall surrounded the elevators. Santilli told Baker, "She says it's behind those mirrors."

Baker, who is president of the homeowners association of the Sulgrave Regency condominiums, consulted with his board of directors. Nobody remembered a mosaic, even 20-year residents. But everyone was intrigued, and the consensus reaction was, "By all means, let's take a look," Baker said.

Three days later, about 30 people crowded into the small lobby to watch as a mirror expert and maintenance staff tried to locate the hidden treasure.

Curious residents chatted excitedly, but Santilli was silent, his stomach tense. He wanted so badly for the mosaic to be intact, but he feared the worst.

Workers chipped off a small section of mirror, then cut a 1-foot-square hole in the plywood backing. Through the hole, everyone could see part of a mosaic, in pristine condition.

"A big cheer went up," Baker said. "It was like being at an archaeological dig and discovering King Tut's tomb right here in our midst."

Seeing that the mosaic was undamaged, he gave the workers the go-ahead to pull off the rest of the mirrors.

Standing at the front of the onlookers was the 91-year-old woman whose delicate hands had placed each of the thousands of tiny pieces of Italian marble more than 50 years earlier.

In the 1950s and '60s, Gabriella Polony-Mountain was at the peak of her career. The Hungarian-born emigre collaborated for decades with prominent Kansas City architects, including Edward Tanner, Peter Keleti and Howard Nearing, on large-scale artworks in banks, churches, schools, hospitals and private homes.

She won prestigious national fellowships, received an award for contributions to American culture from the Daughters of the American Revolution and earned honors from the local chapter of the American Institute of Architects.

And yet, until Santilli mounted an exhibition of her work in May (her first ever in Kansas City) and embarked on a quest to locate dozens of her commissions in public and private buildings around the region, almost no one in Kansas City had ever heard of her.

Walking through the showroom at Kansas City Upholstery, 4646 Belleview Ave., where "Through Gaby's Eyes" is on display through the end of October, the first thing that strikes you is the diversity of media that Polony-Mountain worked in.

Sculptures in travertine and granite, high-relief copper panels, marble mosaics, stained glass and woven tapestries all vie for contemplation.

Abstracted figures of dancers, horses and birds faintly echo Picasso, Chagall, Klimt and earlier masters such as El Greco, even the ancient Assyrians.

And yet certain elements orbs, undulating lines, elongated forms appear again and again, like a signature.