When it was built, many critics called the building too extreme, and lacking in style. Others found in its lack of ornamentation the natural extension of its commercial purpose and an expression of modern business life. Early 20th-century European architects found inspiration in its attention to purpose and functional expression. It was one of the first buildings named a Chicago Architectural Landmark in 1958. It was added to the National Register of Historic Places in 1970, and named as part of the National Historic Landmark South Dearborn Street – Printing House Row North Historic District in 1976. Modern critics have called it a "classic", a "triumph of unified design", and "one of the most exciting aesthetic experiences America's commercial architecture produced".