This volume is a photographic exploration of the hidden and often abandoned infrastructure of New York City. Inaccessible and unknown, the structures and machinery captured in the black-and-white prints deliver the essential services that a city's inhabitants usually take for granted. Many of the vast and imposing facilities have been neglected or have fallen into disuse. Others remain intact and in continous use. Together, the images document how a city works, its technological evolution since the 19th century and the toll that deterioration and years of deferred maintenance can take on a city. With a 4 x 5 monorail view camera and using only available light, Greenberg photographed sites in all five of New York's boroughs, many now permanently sealed in the interests of national security. Among the "invisible" places recorded are the massive valve chambers in the water tunnels 300 feet underground and other features of New York's water system; the anchorages of the Brooklyn, Manhattan and Verrazano Narrows bridges; the dry dock at the Brooklyn Navy Yard; the derelict power station at Floyd Bennett Field; the turn-of-the-century steam turbine in Brooklyn's Pratt Institute; crumbling ruins on Ellis Island and Roosevelt Island; hidden sections of Grand Central station and the Cathedral Church of St John the Divine; the West Side rail yards in Manhattan; the secret Nike missile silos in the Bronx; one of the last remaining manual switch rooms in the new york subway system; the faded grandeur of the City Hall Subway Station, its bronze chandeliers and leaded glass ceilings still largely undamaged; and the vast Brooklyn Army Terminal, once the world's largest warehouse. Greenberg's photographs of this hidden city uncover forgotten engineering feats, examples of skilled craftsmanship and clues about New York's industrial past, as well as revealing the increasing aesthetic apathy of modern builders. His images chronicle both the beauty and the banal necessity of this legacy, threatened by public ignorance and bureaucratic indifference.