The ancient city of Rome--the 'eternal city' according to the Roman poet Tibullus--has been the subject of intense excavation since the establishment of modern archaeological methods in the 18th century. Yet despite this abundance of data, both archaeological and textual, remarkably little has been published regarding the historical development of the city's neighborhoods during its rapid urbanization in the last 300 years of the Republic (4th - 1st BCE). By combining a close reading of the ancient evidence with theoretical frameworks drawn from urban studies, sociology, and folklore, my book offers a novel reconstruction, "from below", of the importance of neighborhoods and practices/ideals of neighborliness to Republican Rome's social and political culture.