This chapter provides a very short overview over the history of American grand hotels and of the Waldorf-Astoria in particular. It focuses on three aspects to show that the Waldorf is a site of modernity: first, the hotel's built structure and technology, second the new developments in the organizational structure of hospitality, and third, how the hotel initiated changes in societal behavior by providing new kinds of spaces for interaction. The existence of the great public rooms of the Waldorf-Astoria provided New York society with a "new toy". Not only the press and Waldorf insiders but also contemporary well-known writers commented on the New York institution. The Waldorf-Astoria was not the first modern hotel structure in America, even if several historians of the hotel call it "the mother of modern hotels" and "the first really American hotel". The progressive features installed in the Waldorf-Astoria provided New Yorkers and visitors a new experience in hoteldom.