In the fall of 1977, Paul Rudolph visited Yale with New York architect George Ranalli, for a show of Rudolph's drawings that Ranalli had curated, and as the two walked up to Yale University's Art & Architecture Building, which Rudolph designed when he was head of the architecture school, he broke into tears: "What have they done to my building?"

One of the most original talents in American architecture, Rudolph poured himself into the design of the A&A building, which opened in 1963. At a gateway corner pivoting New Haven into the campus, Rudolph sited a monumental play of interlocking spaces and cubes pinwheeling off four massive service piers. The design recalled the concrete masts of Frank Lloyd Wright's Larkin Building in Buffalo, N.Y., demolished a decade earlier. Rudolph brought a dazzling complexity to Wright's four-poster idea, with blocks of form and space pushing and pulling back and forth, up and down, in a 10-story building terraced into some 37 levels. He re-established the 20th century monument, and in the process actually solved Wright's conundrum about how to bring Prairie architecture to the dense city: Wright broke the box horizontally, and Rudolph, vertically.

Rudolph had every reason to weep when he returned in 1977, because the building displayed awful mistreatment. Two years after it opened, the building was already ridiculed, if not vilified, by architects who were building their own reputations by tearing it down. Charles Moore, who succeeded Rudolph as dean, mounted the first iconoclastic offensive by building a tongue-in-cheek Mylar "ridicula" in the heroic jury space on the piano nobile. Robert Venturi targeted Rudolph as the architect to demolish in Complexity and Contradiction in Architecture: The building was a duck rather than a decorated shed. The coup de grâce was a disastrous fire of dubious origin that only confirmed the building's status as a pariah.

With the near-total eclipse of Postmodernism, it is ironic that the very figures who opposed Rudolph are burying their previous positions, some with a convenient amnesia. Venturi has formally apologized for his writings, and Robert A.M. Stern has officiated, as current Yale dean, over the comeback of the building, positioning himself as Rudolph's cultural successor. The A&A building, now called Paul Rudolph Hall, was recently restored by Charles Gwathmey, and, in a complex oedipal act, Gwathmey also just completed an extension on the building's north (campus) side, the 87,000-square-foot Jeffrey Loria Center for the History of Art.

First, we must all be grateful that after some 40 years, the building has been restored to the canon as one of the great moments and monuments of 20th century architecture. The structure has been treated with great respect by architects who consider themselves heirs to the Rudolph tradition and by a university that acknowledges the building as a primary icon from the period of courageous architectural patronage under president A. Whitney Griswold (who also hired Kahn, Saarinen, and Bunshaft). Pace.

The first task of restoration was to strip off all the indignities, the partitions that had smothered Rudolph's vectorial spaces. As in a quarry, the concrete defined forms that shaped and directed space, and Gwathmey Siegel & Associates clarified the forms to liberate and restore the space. The massive concrete itself proved an obstacle for new systems. The architects, with associate partner Thomas Levering as project manager, simply bypassed the problem, attaching ducts inconspicuously outside the structure, then weaving them through dropped ceilings into the interiors.

The earnest and respectful restoration sadly misses several germane issues. One of the most regrettable misunderstandings stems from the fact that Gwathmey, despite his status as a Rudolph student, represents a different Modernist tradition. Rudolph slips planes and volumes past each other, creating a relational environment of independent parts, whereas Gwathmey meets corners and volumes in a flush architecture of modular agreement: Gwathmey obeys the grid that Rudolph escapes. Rudolph's buildings tend to great complexity, whereas Gwathmey's tend to simplicity. Whenever Gwathmey adds a dropped ceiling, or even a bookcase, he makes coincide lines that Rudolph would have intentionally misaligned. The Gwathmey edit tames Rudolph; it also undoes Rudolph's space-defining changes in floor and ceiling levels by making them flush and continuous. The lowered ceilings and raised floors may accommodate ducts, but they also diminish the A&A building's spatial variety.

Tonally, the restoration undermines the tactility of Rudolph's building. Dubbed Brutalist, it was brut only in the French sense of the word "raw." The original represented an embodied materiality, down to the patterns that the board forms imprinted on the concrete (which often figured as starting points for bawdy student graffiti in the bathrooms). In an architectural world that would soon capitulate to Sheet rock via its surrogate, foam core, the Rudolph building was overwhelmingly physical: You could scratch your back like a cat on the corduroy walls and punch your fingers into the squishy (and carcinogenic) asbestos fire retardant sprayed on the ceilings.

The restoration architects, however, import materials that are slick and commercial. The dropped ceiling panel system is completely out of character with the original, its low-gloss, vinyl-looking surface at odds with the concrete. The panels, actually made of metal, now take the ceiling out of Rudolph's highly material 3-D surround, denaturing the concrete lid in a jarring tonal lapse. Similarly, wooden floors, raised to the level of the surrounding concrete terraces, domesticate the spaces and reverse the spatial differentiation defined by the level changes. Gwathmey Siegel replaced Rudolph's hemp curtains with neat but bland roll-down shades.

Adding onto a masterpiece is a thankless task, especially if the new budget doesn't match the original. Richard Meier was first tapped to design the addition, but his design proved too expensive. Yale turned to Gwathmey, who had worked with Rudolph on the production drawings for the building, to design the $126 million project.

Rudolph had always anticipated an addition for the art department, so he sited his elevator core off center, on the campus side, where it was intended to become central to the expanded building. That elevator core should have been the starting point of the addition, but Gwathmey suppressed the old elevators for new ones, believing the originals too small for current needs. Rather than consolidating the two small elevators into a larger one within the existing shaft, or adding a big bypass elevator adjacent to the old, the architects created a new bank of elevators, then trivialized the old, vacant shafts by adapting them (and the bathrooms opposite) into coat and photocopier rooms and service areas.

Rudolph intended that the elevator core hyphenate the two buildings, but the addition loses the hyphen, muddying the parti that Rudolph anticipated with such great clarity. The building now has two cores, one suppressed, and visitors to the building are encouraged to ignore the ceremonial flight of stairs up to the piano nobile of the Rudolph building. Instead, they step in at street level through Gwathmey's new, much more prosaic entrance.

What Gwathmey does get right is that he separates the old building and the addition by a public space that acts as a skylit courtyard between the two. The courtyard, which serves as a lounge and reading room for the expanded library, binds the old building to the addition by a void.

To avoid a mimetic response to Rudolph's design, Gwathmey strikes out on his aesthetic own, creating a collage of volumetric parts in shifted and angled geometries. But the façade of near-volumes along the street drifts off into the depth of the site without the sustained discipline of Rudolph's four-poster building. Gwathmey did not have to match the A&A building in grandeur or weight, but he did need to create an addition with a presence that would balance the old building. Compared with Rudolph's, the forms and composition are weak, and all the more so because they are clad in limestone and zinc panels, some laid horizontally and some vertically. The materials look, and are, insignificant seen against the very robust concrete. The Rudolph building had body; Gwathmey's is dressed.

Rudolph designed a strong-willed, handmade masterpiece, and any addition, no matter how well intended, starts out behind the eight ball. Gwathmey's addition courteously defers to the original, but the better way to honor Rudolph's A&A would have been a response equaling its power and presence. Rudolph, who was ecumenical as dean, would have enjoyed—and even demanded—a building that took on his own, mano a mano. This is a commission that asked for brilliant parity among architectural equals, but standing now at this pivotal corner is a perpetuation of the student–teacher relationship.