Two weeks ago, I wrote in this column about 100 Park Ave., a 60-year-old building that has been splendidly reclad and fundamentally reconceived by the relatively little-known firm of Moed de Armas & Shannon. But the activities of the firm are even more extensive than I understood at the time. It turns out that this team has displayed equally exquisite judgment in recladding several other Midtown structures, and best of all, they have created an entirely new office tower from scratch, 510 Madison Ave., which is fast approaching completion.

If there were a firm at work today that could be identified with a house style, especially as regards the exteriors of its projects, that firm is Moed de Armas & Shannon. Of all the architects now plying their trade in New York City, these are the most resolute in their unshakable faith in the redemptive purity of modular Modernism. Whether in their superb green and gray recladding of 340 Madison Ave. or in their all but completed recladding of the Verizon Building at 1095 Avenue of the Americas, they have reconceived a drably Modernist structure by deploying across its surface a gossamer-like covering that proudly avows its pure right angles and its uninflected flatness. As such, this firm can be viewed as a reborn version of a fairly familiar type of architectural firm in mid-20th-century Manhattan. Firms such as Emery Roth & Sons, Bien & Bien, and Kahn and Jacobs applied largely the same style consistently to the same building typologies, whether office slabs and towers or residential projects.

But there is one all-important difference. The architects at Moed de Armas & Shannon are masters of what they do, whereas the highest ambition of their predecessors was nothing more than parsimonious competence. Indeed, it is fair to say that this firm has transfigured those earlier projects from the most insulting hackwork into something whose cultural consequence attains to the status of art. Or to express the matter in the simplest possible terms, these architects have taste. How rare and underrated a quality that is, taste. Likewise the simple satisfaction of knowing that you are in the presence of a team that, without theatrics, without obstreperous postures or manifestos, silently and serenely understands what on earth it is doing.

In 510 Madison Ave., Moed de Armas & Shannon has created an entirely new building for Macklowe Properties, for which this firm memorably created, two years ago, the Apple Cube in front of the former General Motors Building at Fifth Avenue and 59th Street. The new building is a 30-story office tower between 52nd and 53rd streets that, according to the Macklowe Web site, will contain a restaurant, a swimming pool, and a health club.

The Web site provides a rendering of the building that hardly does it justice. In the image, it looks like yet another boring Midtown tower. But it is much more than that. Rising above a similarly clad six-story base, this structure is immediately striking because of the sustained purity of its modular skin. It has such courage and confidence in the sufficiency of this one formal trope that it does little or nothing to vary it, the way a firm such as Skidmore, Owings & Merrill has done repeatedly in comparable projects over the past 10 years. There is no teasing or texturing of the surface, no addition of ribs or flanges, no shift or modulation in color.

And yet the result, like a painting by Agnes Martin or a minimalist installation by James Turrell, is not only beautiful in itself, but rich in a contextual and experiential suggestiveness that reaches far beyond the spare and manifest terms of its art. To stand before this or many another of the firm’s projects is to experience a consoling purity akin to diving into cool water on a summer’s day. Each is an oasis of trancelike serenity amid the blaring sirens, the streetlamps, and the pedestrian onslaught of Midtown.

In project after project, Moed de Armas & Shannon has cleaned up the mess caused by mid-century Modernists. In the process, especially with the new addition of 510 Madison Ave., this firm has left Midtown a nobler and lovelier place than it found it. When you add it all up, there is no one team at work today that has done more the improve the urban fabric of Manhattan than this little-known firm of Moed de Armas & Shannon.