He is best known for his works of Modern architecture, including the Glass House in New Canaan, Connecticut, and his works of postmodern architecture, particularly 550 Madison Avenue which was designed for AT&T, and 190 South La Salle Street in Chicago.
Ia dikenal atas karya-karya arsitektur modern buatannya, yang meliputi Glass House di New Canaan, Connecticut, dan karya-karya arsitektur pasca-modern buatannya, terutama 550 Madison Avenue yang dirancang untuk AT&T, dan 190 South La Salle Street di Chicago.