During the past decade social scientists have been called on more than ever before to address themselves to problems of directed social change in the United States. The effectiveness of federal programmes is severely hampered by the very nature of local government in the United States. Low-income people do not decide what kind of housing they are to have; instead, this is decided by middle-class architects, agency bureaucrats, and city councils. Once policy makers have a clear understanding of the basic causes of poverty and the changes in the socio-economic system that are essential to eliminate poverty, it becomes possible to design programmes in a more rational way. The past few years have seen the end of the New Deal era in American public policy, an era in which society has gone far towards assuring most Americans a life of unparalleled affluence and domestic security.