The corporate campus of America Online Inc. may only be a babe in the Loudoun County woods, but it is, by any measure, an extremely fast-growing 3-year-old.

If the architecture doesn't project the kind of consistency one might expect from a $5 billion-per-year star of the high-tech economy--or the venturesomeness one associates with the electronic age--the main reason may be: There simply hasn't been time.

When the company bought a 154-acre chunk of an underdeveloped office park on Route 28 near Dulles International Airport back in 1996, it was stuck with a mediocre headquarters building already on the site. "We were happy to get it," says AOL Vice President Faith Denault. "We needed land with a building we could move into immediately." In a matter of months offices were remodeled and executives moved in.

If anything, the pace has quickened since then--it seems as if a new building pops up every few months. More than 2,000 employees now work on campus; within a year or so that will increase to about 3,500. Happily, as the campus has grown the architecture has improved dramatically.

It remains true, unfortunately, that the tapered, five-story headquarters building, constructed in 1991 for a different company, is the tallest and most prominent structure on the campus. It is a concrete-panel and ribbon-window affair all too typical of the middling modernism of Northern Virginia office parks. The anonymous architecture certainly belies the fact that this is Mission Control for the world's largest Internet provider.

Alas, it also is the case that the suburban office park pattern of the AOL campus--when completed it will serve 6,000 employees--is a major contributor to sprawl in the Washington region, and the concomitant increases in traffic and pollution.

The talk these days in Northern Virginia politics is all about traffic, but for the most part the politicians do not get to the heart of the matter: The biggest causes of jammed roads are land use policies that encourage spread-out, auto-dependent developments such as the AOL campus. Route 28 is a traffic nightmare ready to happen, and there is nothing architecture--good, bad or indifferent--can do about it.

Still, architectural excellence definitely is preferable. The crisp, metal-and-glass aesthetics of two recently completed buildings--Creative Centers 1 and 2--do wonders for the AOL campus. They are machines in a garden, and they set a more positive, with-it tone.

They were designed, not incidentally, by the Washington firm of Ai, formerly an interiors-only design company experiencing a sort of gala coming out party here as a provider of full architectural services. Ai did the master plan and, so far, has designed four "creative centers"--two still under construction--as well as a huge, low-lying building for communications equipment, and three parking garages.

The two completed centers are, above all, commodious workplaces. Indeed, the emphasis on high-quality shared spaces in the two buildings--conference rooms, cafes, courtyards--demonstrates that the need and desire for direct human contact remains strong even in the heart of cyberspace.

Creative Center 1, which now houses several hundred computer programmers, is an inventively reconstituted warehouse. Some refer to it as "the hangar" in memory of the aircraft engines and other huge odds and ends once stored there by British Aerospace Inc., its former owner.

A perfect container for offices the hangar was not--475 feet long, more than 200 feet wide and 30 feet tall from floor to ceiling. One of the long sides was a windowless wall, the other a sequence of loading docks projecting in a sawtooth rhythm. Skylights were few and far between.

The client liked the idea of converting a warehouse. "These are creative people and hard workers," says Denault, "and we truly wanted to create an environment that they wanted to be in--the tag word, I guess, would be 'funky space.' "

Clearly, the overriding tasks facing the Ai architecture team headed by David Haresign and J.P. Spickler was to break down the overweening scale of this big box and bring in some natural light. Taking advantage of the high ceilings, they inserted a second floor, and then went about dividing the space, in Haresign's words, "into a series of villages."

Using the angles of those loading bays as starting points, the architects partitioned the interiors with rows of private offices arranged in sweeping curves and faced with translucent glass--each row fronting a grid of open-office workstations. Then, each of the resulting "villages" was supplied with a sky-lit core containing mechanical rooms, rest rooms, open areas for informal gatherings and a sharp-looking steel stairwell suspended in space. The materials and the warehouse aesthetic--exposed steel structure, metal and glass fixtures, polished concrete floors--are right at home.

AOL got its wishes here. The offbeat atmosphere inside the big box really is a bit funky--for an office, anyway--and enormously pleasant. The internal divisions are suggested on the outside with a series of angled, two-story bays housing conference rooms. Sheathed in glass and silvery metal panels, these projections transform a dumpy warehouse into one of the best-looking long facades in the Washington area.

Literally and metaphorically, four-story Creative Center 2 takes up where No. 1 leaves off--the buildings are connected by an enclosed passageway and, naturally enough, architects Haresign and Spickler (joined by Steve Kahle) continued the same design vocabulary. Outside and inside, Center 2 is stiffer than Center 1--"more corporate," Haresign says--but it, too, is a skillful, pleasing product.

And it is even longer. The glass-and-silvery-metal curtain wall of the 500-foot primary facade is broken up successfully with a series of simple vertical notches. On the attractive, concrete-and-glass rear facade--the switch to concrete matches up better with the surfaces of Center 1--the system is reversed, and the notches become column-like protrusions.

As in Center 1, there is an emphasis on shared spaces--a multipurpose auditorium, a cafe-atrium and, most notably, a beautiful exterior courtyard between that rear wall and a parking garage. (The landscape architecture was done by the Alexandria office of EDAW.)

Creative Centers 3 and 4, still under construction, will be at least a little bit strange. Inside, Denault says, the workplace environment will be a match for those of Centers 1 and 2, but the buildings were intentionally designed in a more mundane, mediocre style. Ribbon windows and concrete panels will contrast with corners of metal-and-glass, in an obvious attempt to meld the architecture of the 1991 headquarters building with the more advanced style that came after.

A very, very curious gambit--but realistic, and darkly funny. The idea, Haresign says, is to create an "exit strategy" should AOL ever want to sell off part of its campus. For the conventional office park market, you see, custom-made won't do. Another way to put it is: Mediocrity sells.

Also in the plan is a so-called "student union" building situated in the middle of the grassy plain in front of Creative Center 1, housing facilities for the entire campus community. Although this could be a work of architectural sculpture that would give lasting character to the entire campus, it has been postponed indefinitely, according to Denault. "We decided at this point in time to focus our energies on providing for the population of the campus," she said. Translation: The office buildings come first.

If I were king, or maybe just AOL Chairman Steve Case, I would do something about the humdrum headquarters building and I would construct the "student union" forthwith. My instructions to the architect would be: Make it a masterpiece.

CAPTION: Linking up nicely: Creative Center 2's concrete-and-glass rear facade is joined to Creative Center 1 by a covered passageway.

CAPTION: A glassed-in stairwell at Creative Center 1, a warehouse conversion whose aim was to add a with-it tone. Mission accomplished.

CAPTION: The sky-lit atrium-cafe in the four-story Creative Center 2, one of many welcoming shared spaces on the campus.