Renzo Piano and Richard Rogers's Centre Georges Pompidou of 1971-1977 - the true prototype of the modern museum as popular architectural spectacle - wound up costing so much more than planned that the French government solved the shortfall by cutting support for several regional museums.

What a museum chooses to exhibit is sometimes less important than how such decisions are made and what values inform them. To have the crucial role of museum professionals usurped by self-serving tycoons in the name of economic imperative threatens not only the integrity of individual institutions but the very principle of art held in public trust.

Before the professionalization of architecture in the nineteenth century, it was standard for an aspiring mason or carpenter to begin his apprenticeship at fourteen and to become a master builder by his early twenties.

Although prefabrication has a long history - the ancient Romans shipped pre-cut stone columns, pediments, and other architectural elements to their colonies in North Africa, where the numbered parts were reassembled into temples - the idea took on a new impetus with the technological advances of the Industrial Revolution.

Before World War II, Modernist architects sometimes had to resort to custom fabrication or outright fakery to achieve the machine imagery advocated by the Bauhaus after its initial, Expressionist, phase. Stucco masqueraded as reinforced concrete; rivets were used for decoration.

One of the Age of Enlightenment's most hypnotic images is Ledoux's rendering of his neoclassical theater of 1775 - 1784 in Besancon, surreally reflected in the colossal eye of an unidentified cosmic being.

There is no sadder tale in the annals of architecture than the virtual disappearance of the defining architectural form of the Modern Movement - publicly sponsored housing.