It goes without saying that, even before the arrival of Richard Armstrong, the Carnegie Museum of Art was a first-rate institution. What it needed was a visionary like him to prod it to the next level.

When Mr. Armstrong leaves his position at the end of the year, he will leave behind exceptionally big shoes to fill.

In 1992, the museum recognized his taste for what works and what doesn't in the avant-garde art world by making him curator of contemporary art. A discerning understanding of contemporary art and of the institutions and patrons that surround it was a talent that served Mr. Armstrong well at his previous stint at the Whitney Museum of American Art in New York.

Because of his expertise, Mr. Armstrong was tapped to organize what would become the wildly successful 1995 Carnegie International. After staging an aesthetically important exhibition that also intrigued the public, he was appointed the Henry J. Heinz II director of the Carnegie Museum of Art in 1996.

In addition to an unerring eye, Mr. Armstrong has a talent for managing, organizing and raising money -- an enviable quality in museum directors. Today, the Carnegie Museum of Art is in excellent fiscal health because of it.

Along with acquiring future masterpieces for its permanent collection, Mr. Armstrong understood the importance of renovating galleries and infrastructure. He also built a first-rate curatorial and teaching staff that will continue its tradition of excellence long after he's moved on.

No one is truly indispensable in the art world, but Richard Armstrong comes close. His sure gaze and steady leadership will be missed.