NEW YORK—It’s not a house, it’s a work of art. Keep that in mind as you contemplate the $15–25 million estimate Christie’s has placed on Richard Neutra’s Kaufmann House, a glass-box modernist jewel in the hills of Palm Springs, California. Although the auction is officially being conducted under the auspices of Christie’s Real Estate, the house will be offered at the Postwar and Contemporary Art sale in New York on May 13, as the auctioneers hope to capitalize on the repositioning of architecture and design as fine art— or at least on the collapsing of the distinctions between these things.

As a dwelling, the Kaufmann House is in some ways quite modest. With only 3,200 square feet and five bedrooms, it distinctly lacks the palatial quality in vogue today. But as an incarnation of California Modernism it is second to none. Built in 1946 for department store tycoon Edgar J. Kaufmann Jr., it was lovingly photographed the next year by Julius Shulman (still active at age 97), whose pictures have done much to make the house iconic. As one of the last domestic designs executed by the great Viennese-born architect, the house gives full expression to Neutra’s idea that a home should be integrated with its surroundings. The glass walls, which slide open, seem almost to disappear, and the front entrance is de-emphasized by being recessed. Some of the rooms are actually outdoors, shielded from the elements by a system of pivoting fins. The low, flat roofs add to the sense that the house is horizontal rather than vertical, and that it blends into its environment instead of towering above it.

While the Kaufmann House is considered by architecture critics to be one of the most important modernist residential structures in the world, it was badly neglected for decades after the death of its original owner. In 1992, Brent and Beth Harris, a local couple with an interest in architecture, bought the house for $1.5 million. The property was virtually a teardown; the land was considered more valuable than the house. The Harrises hired two Los Angeles architects to perform a painstakingly accurate restoration. They also acquired more of the adjacent land, to enhance the house’s surroundings. The Harrises are the consigners for this sale.

The appreciation of modernist houses as works of art has increased in recent years, to the point that people are actually collecting and curating them. To put the Kaufmann House’s estimate in perspective, consider these auction results: Mies van der Rohe’s Farnsworth House near Chicago (1951) was sold by Sotheby’s in 2003 for $7.5 million; Pierre Koenig’s tiny Case Study House #21 in the Hollywood Hills (1958) went for $3.2 million at Wright in December 2006; and Jean Prouvé’s Maison Tropicale (1951), a moveable prototype of a prefab structure intended for French colonists in Niger, sold at Christie’s for nearly $5 million this past June. But none of these remotely approaches Christie’s expectations for the Kaufmann House, and the auctioneers are betting that modernism mania will work its magic.