Who owns -- and, more important, controls -- the design of a work of architecture, as opposed to owning the work of architecture itself? When does a work of architecture or its design become inviolate and unchangeable, if ever?

These questions arise whenever someone proposes to alter or add to an existing design or structure, and in many cases such proposed changes provoke heated controversy.

The most controversial modifications involve publicly acknowledged historic buildings or sites. Recall, for example, the fuss over expanding and renovating the U.S. Capitol two decades ago. Or imagine the fuss if classical column ornamentation were proposed for the Washington Monument.

Not-so-old buildings designed by well-known architects, or buildings that have become local landmarks, also can be the subjects of legal, economic and aesthetic battles in which the forces for preservation clash with the forces for alteration.

Among the more notable conflicts:

Expansion of the Kimball Art Museum in Fort Worth, Tex., designed by Louis Kahn less than 20 years ago, was blocked by strict preservationists, many of them architects, despite the museum's need for more space.

Opponents were against any change, even an addition echoing the form of the original structure, and despite the fact that the addition had been designed by Kahn's close and very talented colleague, Romaldo Giurgola. Certainly one of Kahn's finest works, the Kimball Museum is considered by many architects to be immutable and incapable of expansion.

Lever House, one of Manhattan's first and most famous postwar, high-rise, glass curtain-wall office buildings, designed by Skidmore, Ownings & Merrill, was declared a historic landmark by the city after its owners suggested enlarging it or replacing it with a bigger building.

Two other landmark buildings in Manhattan, both museums, have been embroiled in design modification controversy.

The Whitney Museum, designed 30 years ago by Marcel Breuer, was to be substantially enlarged with an addition by Michael Graves. Graves produced several schemes, each of which was condemned by critics, professional and otherwise, for violating Breuer's original work. The project is pending.

Frank Lloyd Wright's Guggenheim Museum also was the subject of a fight over an expansion, designed by Gwathmey-Siegel. Some accepted the notion of expansion but disliked the new design. However, many preferred to see nothing changed, inside or out, insisting that Wright's spiraling structure was a whole and complete form to which nothing could be successfully appended without destroying the form's integrity.

An ongoing battle is being fought over control of the design of the Korean War Veterans Memorial, a project yet to be built on the Mall just south of the Reflecting Pool.

A national design competition produced a winning design chosen by a jury of veterans and design professionals. But the currently proposed design differs substantially from the winning design; the memorial sponsors switched design teams and drastically revised the concept first chosen by the jury.

The latest design retains conceptual fragments of the winning design but otherwise embodies a totally different compositional strategy and symbolism. With its design concept compromised, the winning design team has filed suit against the sponsors and their architects, claiming that contractual obligations, as well as ethical standards, have been breached.

Similar disputes have surrounded changes to other kinds of works of art -- colorizing movies originally made in black and white, restoring or enhancing paintings or sculpture, performing plays with abridged dialogue and scenes omitted or added -- without the author's approval.

But is architecture really that kind of art?

Does an architect enjoy the same rights as the artist who paints a picture or the author who writes a novel? Should an architectural work be subject to change only with the designer's blessing? Do copyright laws, which can limit use of drawings showing an architectural design, also protect the design itself?

An attorney will tell you that, for most works of architecture not protected by some governmental umbrella, the answer to all of these questions is decidedly "no."

Only a specific and irrevocable contract between owner and architect, one creating a deed covenant, can prevent owners and designers from subsequently amending the original architect's design. Otherwise, building owners have absolute dominion over the architectural fate of their properties, constrained only by local zoning regulations and building codes.

For architects commissioned to redo buildings whose renovation and alteration are seen as welcome occasions for aesthetic betterment, this legal reality is a blessing. In these instances, few will appear to defend the original architect's interests or the integrity and historical merit of the original architectural design.

Conversely, architects frequently feel cursed when their own beloved designs are later modified by people whom they believe possess less talent, taste and wisdom.

Indeed, it is common to hear architects complain about their own clients compromising a design by choosing the wrong colors and furniture. Imagine how much worse they feel when their design is reshaped, restyled or superseded completely by the intervention of others.

Of course, buildings per se are not the same as books, paintings, plays or orchestral compositions, nor are they the same as the design for the building.

Whether we like it or not, most built works of architecture are utilitarian products, bought and paid for by their owners, who rarely are driven by aesthetic impulses. In most cultures, the genesis of building is the need for shelter and safety for human habitation and activity. And most buildings are in fact shaped by many minds and hands, not by the mind and hand of a single artist. Therefore, neither the public nor the courts are inclined to treat buildings as untouchable, cultural artifacts.

Yet architects, their occasionally inspired patrons and a relatively small number of historians and critics have elevated architecture to the plateau of art. Fortunately, because enough meaningful architecture has been built, preserved and admired, people accept the notion that at least some architecture -- and not just monumental civic buildings -- is indeed a form of cultural expression worthy of promoting and protecting.

Thus, despite the functional and economic origins of construction, the architect's greatest challenge is to create buildings that transcend utilitarianism to become, in the eye of the public, true art. Inspired design, more than contracts and covenants, probably will continue to be the most effective preserver of the architect's original work. Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland.