Steadfastly modernist architect Charles Gwathmey died Monday in New York City. He is best known in the art world as the architect responsible for the renovation and addition to the Frank Lloyd Wright designed Guggenheim Museum in 1992. Other notable museum buildings in his portfolio include the American Museum of the Moving Image, the International Center of Photography, as well as an addition to the Fogg Museum, among numerous others. His firm, Gwathmey Siegel also worked for numerous celebrity clients, building residences, in addition to his commercial work. The Ingalls Library holds several volumes on his work.