Cass Gilbert, American architect, designed the United States Supreme Court Building and Woolworth Building (d. 1934)

Cass Gilbert (November 24, 1859 – May 17, 1934) was a prominent American architect. An early proponent of skyscrapers, his works include the Woolworth Building, the United States Supreme Court building, the state capitols of Minnesota, Arkansas and West Virginia; and the Detroit Public Library, the Saint Louis Art Museum and Public Library. His public buildings in the Beaux Arts style reflect the optimistic American sense that the nation was heir to Greek democracy, Roman law and Renaissance humanism. Gilbert's achievements were recognized in his lifetime; he served as president of the American Institute of Architects in 1908–09.

Gilbert was a conservative who believed architecture should reflect historic traditions and the established social order. His design of the new Supreme Court building (1935), with its classical lines and small size, contrasted sharply with the large federal buildings going up along the National Mall in Washington, D.C., which he disliked.Heilbrun says "Gilbert's pioneering buildings injected vitality into skyscraper design, and his 'Gothic skyscraper,' epitomized by the Woolworth Building, profoundly influenced architects during the first decades of the twentieth century." Christen and Flanders note that his reputation among architectural critics went into eclipse during the age of modernism, but has since rebounded because of "respect for the integrity and classic beauty of his masterworks".