At Harvard, a road runs through it

(Correction: Because of a reporting error, an architecture review of Harvard's Center for Government and International Studies in the Nov. 20 Arts & Entertainment section incorrectly said the School of Government had moved into the building. The Government Department from the Faculty of Arts and Sciences is housed in the building.)

It's a strange sight on Cambridge Street near Harvard Yard: Two new buildings, both bright orange, face each other across the street. They appear identical. There's something sci-fi about the look of them, with their smooth shapes and big shiny curves, as if they had just touched down from a far galaxy.

The two are, in fact, parts of the same building, Harvard's Knafel Center for Government and International Studies. Knafel is home to either 13 or 17 (depends who you ask) separate institutes, as well as the School of Government. There are three floors of faculty offices, plus classrooms, an auditorium, a cafe, a library, and numerous social spaces.

The two halves of Knafel -- Knafel North and South -- were designed to be joined into one by a wide tunnel at the concourse level, which is one story below the street. Responding to neighbor protest, however, Harvard chose not to seek the necessary permission from the city. Hence there's no tunnel.

Knafel's architect is Henry Cobb, a founder with I.M. Pei of the firm Pei Cobb Freed. Now 79 and showing no sign of slowing, Cobb is the designer of numerous prominent buildings, including Boston's Hancock Tower and Moakley Courthouse.

Knafel is the kind of elegantly understated building that some people love and others hate. Its interior is exquisitely detailed, much of it in delicate panels of wood or glass. Sunlight seems to pour in everywhere, often through screens of warm-toned wood. Stairs are wide and generous, and so are corridors and lobbies. There's an aristocratic sense of spaciousness. On the ground floor of Knafel North, a delightful cafe opens directly onto a green park.

There is, however, a slightly antiseptic, slightly hygienic feel to the place, as if it were an expensive clinic. Cobb is not an architect who wraps you in fuzzy, sentimental memories. He's a minimalist. His Hancock Tower is surfaced with 10,344 identical panes of glass. If there is a culture Knafel seems to rhyme with, it's not the cluttered Western living room but rather the traditional Japanese interior, with its bare walls, spare furnishings, and sophisticated system of proportions. Cobb's panels of clear glass, frosted glass, and pale wood recall the shoji screens and tatami mats of Japan.

At first glance, it's possible to see the Knafel as generic corporate space, costly but characterless. But a second look reveals an infinite degree of care and invention. Despite some eccentricities, Knafel is one of the few good contemporary buildings Harvard has built.

The exterior, admittedly, is odd. It's entirely surfaced in either clear class (upper floors) or orange terra cotta (lower ones). ''The terra cotta will mellow over time," says Cobb, referring to its color, and doubtless he's right. The problem is that while terra cotta is a very hard ceramic material, it's detailed here to look, at least to the casual glance, like flimsy siding. Cobb wanted his building to live comfortably with two very different neighbors, the residences on one side and Harvard buildings on the other. The terra cotta is supposed to mediate between them by reminding you of both: of clapboard wood houses, because it's shaped in long horizontal strips, and of brick university buildings, because (like brick) it's fired clay. But the visual effect is too much like vinyl or aluminum.

Another oddity of the Knafel is that in both halves, there's a lot of floor-to-ceiling glass at upper levels facing south and west. In seasons when the sun is low in the sky, as it is now, the afternoon glare would make rooms uninhabitable if it weren't for Cobb's system of wood Venetian blinds (which, if you pull them down, rise automatically overnight). The blinds help a lot, but less glass would help too. And taking the glass to the floor means you can't furnish against it. It's a case where Cobb's minimalism -- all glass all the time -- works against the comfort of the inhabitant.

I asked Cobb why the two halves of his building appear identical, like a peach sliced in half and pulled apart. As always, his reply is thoughtful. ''It was the only way to make it look like one single complex, not divided into a we/they," he says.

Originally, Harvard planned to erect the Knafel on another site, where it would have encroached on a green quad behind Harvard's Gund Hall. Neighbors, who used the quad as a park, quite reasonably objected. Cobb helped persuade the university to move to the present dual site. He says that the most important thing about the Knafel is that it preserved this park, which lies behind Knafel North and is fitted out with new trees.

Cobb's design went through the wringer of at least 30 neighborhood meetings. A lot of it is now underground, in the concourse level. The concourse is a surprisingly bright and airy space that contains Knafel's best room, a beautiful skylit library beneath the park. Also beneath the park is an underground loading dock, which was supposed to serve both halves of Knafel using the connecting tunnel.

Why would neighbors object to an invisible tunnel? Wouldn't it be a win for both sides, reducing the number of pedestrians crossing Cambridge Street? John Moos chairs the Mid-Cambridge Neighborhood Conservation District Commission, which reviewed the project many times. He says there is no rational explanation. The anti-tunnel faction was motivated by simple animus toward Harvard.

The tunnel is a case where popular government killed a good idea. Knafel would be infinitely improved by the tunnel. It could have been built without pain during construction of the building. Now it would require tearing up Cambridge Street a second time.

Much as he mourns the tunnel, Cobb praises the neighborhood review process. ''We redesigned the building in accord with a very specific list of eight points they wanted to make," he says. ''It changed radically. It came down from five stories to four, with a smaller footprint and more glass. Those people did a good job."

Robert Campbell, the Globe's architecture critic, can be reached at camglobe@aol.com.