What sets Staten Island apart from the rest of New York City? The island's identity has in part been defined in opposition to the city, its physical and cultural differences, and the perception of neglect by city government. It has long been whiter, wealthier, less populated, and more politically conservative. And despite many attempts over the years, Staten Island is not connected by the subway to any of the other four boroughs.

Kenneth M. Gold argues that the lack of a subway connection has deeply shaped Staten Island's history and identity. He chronicles decades of recurrent efforts to build a rail link, using this history to explore the borough's fraught relationship with New York City as a whole. The Forgotten Borough ranges from when Staten Island first contemplated joining the city in the 1890s to the opening of the Verrazzano-Narrows Bridge in 1964, highlighting pivotal moments when the construction of a subway appeared possible. The economics and engineering of tunnel construction, the difficulty of uniting Staten Islanders around a single solution, competition from the other boroughs, and resistance from powerful corporations and public authorities all undermined a rapid transit connection. Gold demonstrates that the failure to establish a rail link during this period caused Staten Island to diverge culturally, demographically, and politically from the other four boroughs. Drawing on extensive archival research, The Forgotten Borough shows how transportation infrastructure and politics shed new light on urban history.