if by suburb is meant an urban that grows more rapid than its aiready developed intenor, the process of suburban zat on began during the emergence of the city in the second quarter of the nineteenth century. Before that period the city highly compact c G er in which people moved about on and goods were foot the earty factories built in the 1830 s and 1840s were located waterways and near railheads at the edges of cities, and hous ngwas needed drawn he prospect of employment. In time, the s were proliferating mill towns of a nts and row houses that abutted the older, main defense against this t and to enlarge their tax bases, the cities appropriated industrial neighbors. In 1854, for example, the city of Philadelphia most Philadelphia County. Similar municipal maneuvers took place in Chicago and in New York Indeed, most great cities of the United States achieved such status only by incorporating the communities their borders. With the acceleration of industrial growth came acute urban crowding and accompanying social stress conditions that began to approach disasttous proportions when, in 1888, the first commercially successful electric traction line was developed. Within a few years the horse drawn trolleys were retired and electric streetcar networks criss tossed and connected every major urban area, fostering a wave of suburbanization that transformed the compact industrial city into a dispersed metropolis. This first phase of mass scale suburbanization was reinforced by the simultaneous emergence of the urban Middle class whose desires for homeownership In neighborhoods far from the aging inner city were by the developers of single-family housing tracts.