The new World Bank office building is elegant, solid, stolid, big. It can also be described in negatives -- it's not showy, not exuberant, not wholly disdainful but not welcoming. It occupies its prominent southeast corner at Pennsylvania Avenue and 18th Street NW with a certain authority, as if it had been there for years.

It fits, in other words, into one of the city's more unusual settings, a sawed-off sort of Wall Street precinct characterized not so much by architectural mediocrity as by extreme, excessive orderliness. It's a commodious district, in a way -- sidewalks are broad and lined with trees, which soften the architecture, and there's plenty of clipped greenery and, here and there, quiet, shaded places to sit.

But practically all of the buildings are enormous and speak the architectural equivalent of officialese. They are, of course, pretty much uniform in height and they tend to occupy entire blocks. Each has but a single entrance-control point, sometimes an impressive affair but just as often hard to find (head for the center of a block is a good rule of thumb).

Little businesses have not sprouted in the interstices because there are no interstices -- the only leftovers of 19th-century scale are modest churches or a very few residences converted to institutional use. Thousands of bankers and bureaucrats work each day in this calm, toney, regulated environment. When they want to eat out or shop they head mostly north, to the other side of the Avenue.

Successive generations of architects have paid so much attention to matching materials and colors -- it's an area of tan-gray limestones, granites and concretes -- that a certain stylelessness pervades irrespective of a building's style (the mix comprises stripped classical, classic revival and, mainly, monolithic varieties of modern).

Deferring to this custom, the Washington office of Hellmuth, Obata and Kassabaum (Larry Sauer, principal-in-charge, with George Eisenberger, Jerry Davis and Sam Spata) chose a textured salmon granite for the base of the new World Bank building and a superbly matching precast concrete for the upper floors. Their building mirrors the pattern of its neighbors in other key respects -- it extends a full block along 18th Street, it contains no stores (excepting an almost invisible outlet for World Bank publications) and it has a single, centered entrance.

This is altogether a bad pattern if the goal is a vibrant cityscape, but one can credit these architects with twisting the pattern almost enough to make it likable. The building is a behemoth but it's not ponderously institutional; it doesn't hide its bigness but it is relatively easy on the eyes, and it is kinder to the street than any of its neighbors to the south and west, including the six World Bank buildings immediately across 18th Street. (Admittedly this isn't saying much, because that cluster is one of the more rigorously self-enclosed in the city. But here, at least, there are transparent windows on the ground floor. From the street you can see real people -- think of that! -- inside.)

The distinguishing exterior features of the new edifice are its relentless horizontality (basically this is a ribbon-window building thankfully modulated by shadow-catching recesses), its gracefully curved corners, its periodless sort of historical recall (like all traditional Washington office buildings, this one is divided horizontally into three parts) and its fundamental functionalism, expressed in all of those windows (primary client demands were to maximize perimeter offices and natural light) and, especially, in two giant-sized expanses of clear glass punctuating the west fac ade.

These huge, convex windows, each four stories high, break up the horizontal sweep. More importantly, their giantism is fully appropriate to that of the building -- tasteful but not timid, they don't exactly lighten up the neighborhood but they do add a surreal touch that somehow fits. Most importantly, they are the keys to the building's interior -- together with rooftop skylights (hidden from street view) they bring in the necessary daylight.

Inside its forbidding door, the building is pleasant -- it's a good environment to work in and a worthy model for the World Bank to follow as it begins to retrofit its principal compound across the street. (The bank at present has 6,300 employes; it owns nine buildings and rents space in seven.) It would in fact be a good model for many large, hierarchical offices that need to respond quickly to change -- the principal themes of the interior design (done by HOK in close collaboration with Interspace of Washington) are flexibility, efficiency and, above all, the availability of natural light.

The interiors -- extraordinarily open, for Washington, because they're relatively column-free (the basic module is 40 feet by 40 feet rather than the customary 20 by 20) -- focus on the atriums. These are not the gargantuan affairs we're used to seeing but relatively tight, vertical spaces running from Floors 3 to 11 and broken up at intervals by terraces and bridges. They're more like places than big empty spaces -- they can be enjoyed from overlooks on several levels, and they serve as orienting devices. One won't easily get turned around in this building. The atriums are energy-efficient, too. Together with the perimeter windows, and certain "smart" features such as centrally controlled artificial lighting (with individual controls in each office), they will produce energy savings of up to 40 percent.

Not much was left to chance in this highly rationalized office design. The floors, for instance, consist of an ingenious system of metal plates (covered of course with carpet) that can be easily unscrewed; the wiring underneath is easily accessible, and plug-in computer hookups can be inserted at any desirable point. (This feature was so important to the bank that it was willing to give up an entire story of office space to make room for the raised floors.)

Integrated systems furniture modules were used throughout, and apportioned in ways that provide workers with more usable space even though they take up less actual space than those of their confreres across the street. Hallways and aisles are tight, but they almost always terminate at windows -- a vast improvement over Washington's claustrophobic norm. Natural light is the great equalizer here -- everybody gets some. There are very few airless cubicles. The plans combine open- with closed-office layouts, but even the "closed" offices permit light to flow through -- the solid partitions are broken with high clerestories of clear glass at the top.

(A special, if parenthetical, mention should be made of the use of clear glass throughout the building -- this is one of the first large-scale deployments of a new glass with a nonreflective coating that gives the same energy performance as reflective glass. This adds tremendously to the building's likability, such as it is, and it is a development of great potential for midrise D.C. Will we soon see the end of those monster dark ribbon windows downtown?)

Still, even though it's not unimportant that the 1,400 people who work in this building do so in a pleasant environment, and it's necessary to point out that the architects did a fine job without, in the end, breaking the mold, and it's interesting to note that this neighborhood, if such is the word, turned out better than anticipated (it's a lot softer, for instance, than the federal office district in the Southwest) -- even though all of this is true, it is only to say that as a model for city building, this area is a not-unqualified disaster. It represents urbanism of the purified sort -- not vital, not vibrant, not varied.