The National Building Museum turns a quarter-century old this fall, and tonight lots of folks will be celebrating underneath the stupendous Corinthian columns of the museum's Great Hall.

There is, indeed, much to celebrate. First comes the grand old building itself. Those columns and the rest of it likely would be dust today had not Congress, in early December 1980, authorized its use as "as a national center to commemorate and encourage the building arts."

That all-inclusive phrase, "the building arts," had people scratching their heads 25 years ago and, to some extent, it still does. In the breadth of its mission, the building museum was unprecedented.

It is not an architecture museum. Not engineering, not city planning. Not a museum for stonemasons, sheet metal workers, steel fabricators, real estate developers, social historians, taste makers, apartment dwellers, homeowners and . . . the list is almost endless.

But if the museum is not one of these things, it is all of them. To paraphrase Mr. Lincoln, the challenge has been to deal seriously with some of these subjects all of the time, and perhaps to deal with all of them some of the time.

Turning such a balancing act into a cohesive program of exhibitions has proved to be an elusive goal. There have been many more misses and semi-misses than outright hits among the 167 exhibitions held in the museum since 1985, when it opened to the public.

(The first four years were devoted to making basic renovations to the building, which was then nearly a century old and in sorry shape. Renovation continued off and on for another decade and, actually, is not fully done even now. Is a big old building ever "finished"?) Gradually, however, despite many changes in personnel at the top, middle and bottom, the museum has begun to develop a style to fit its broad content. Its best shows possess a strong narrative filled out with original objects, visual and verbal documentation, and evocative exhibitions design.

A long-running current exhibition is a good example: "Liquid Stone: New Architecture in Concrete." It begins with an important, if familiar, subject -- concrete construction is all around us -- and imbues it with contemporary relevance by emphasizing new technical possibilities and innovative design.

"Liquid Stone" also benefits from something too many of the museum's exhibitions have lacked: wider distribution via the Internet (a relatively complete version of the show is on the museum's Web site, www.nbm.org) and a permanent record in the form of a book.

Actually, the "Liquid Stone" book won't be published until after the show closes on Jan. 29. Its lateness illustrates the difficulty and expense of publishing a catalogue for every major exhibition. But such an ambition is important if the museum and its exhibitions are to be taken seriously.

Chase Rynd, the museum's fourth director, replacing the dynamic Susan Henshaw Jones in the summer of 2003, says that such publications are a critical element of his long-term intention "to seriously emphasize the word 'national' in our name."

Part of Rynd's plan is to increase the number of high-level curators from one to three or more. This would enable the museum to initiate more of its exhibitions, rather than relying on outside talent or on other museums.

Rynd also intends to reduce the number of exhibitions to about four per year, down from a dozen or so during the Jones era. This change probably augurs well for the overall quality of exhibitions, but it could decrease flexibility.

Topical relevance has been one of the museum's valuable attributes. For instance, in early 2004 the museum mounted a show titled "D.C. Builds: The Anacostia Waterfront." Showing many signs of having been put together in haste, the exhibition was definitely flawed. All the same, by focusing on a major local planning initiative, it was extremely valuable.

Of course, there are other ways to have immediate impact. Within months of the attacks of Sept. 11, 2001, the building museum sponsored a series of lectures and symposiums called "Building in the Aftermath."

It is hard to imagine another institution that could have initiated such an important discussion so quickly. A similar series, focused on Hurricane Katrina, is in the works.

Hardly a day goes by, in fact, that the museum does not have something going on -- family festivals, noon and evening lectures, films, symposiums, tours.

In addition, the museum is home to innovative educational programs for the area's schoolchildren. In fiscal year 2004 nearly 19,500 kids participated.

Edmund Worthy, vice president for education, has a right to brag. "Our youth programming is even stronger than what we do for adults," he says. "The museum has developed an amazingly strong and broad array of activities that teach young people about design, about the built environment." Some of these programs are being packaged for national distribution.

Improvements can certainly be made. Maintaining a steady stream of donations remains a challenge for an institution whose annual operating budget exceeds $7 million -- and should be higher. (Fortunately, the General Services Administration, a federal agency, takes care of the building itself.) Other needs? The museum lacks a proper auditorium. It has to get more serious about scholarship and publishing. It desperately needs more equipment and people to become a leader in the electronic age.

On the other hand, the "building building," as it was called by several of its founders 25 years ago, has come a long way.

The big old brick pile just north of Judiciary Square was designed by Gen. Montgomery C. Meigs in the 1880s as an office dispensing pensions to Civil War veterans. For much of the 20th century, the monumental Great Hall was almost comically misused as ordinary government office space. Rats, of course, loved the protection offered by the temporary wooden floor.

Yet today the building can proudly -- and correctly -- claim to be the one indispensable stop in Washington for anyone interested in all, or even just some of, "the building arts."

Museum Director Chase Rynd says he wants "to seriously emphasize the word 'national' in our name."The "building building" was originally designed as an office to dispense Civil War veterans' pensions, above; below right, one of its crowning touches.