Research is examining the processes by which persistent and concentrated urban poverty is created, maintained, prevented, or overcome. This paper reports on discussion and suggestions generated in a planning meeting of the Social Science Research Council's Committee for Research on the Urban Underclass held on September 21-23, 1988. Issues explored include the following: (1) the clarification of processes and mechanisms; (2) historically proximate and distant factors; (3) factors affecting the emergence of an urban underclass; (4) an increasingly competitive international economy driving industrial and occupational change; (5) the fact that changes in labor supply and demand have ignored segments of the population, or have made alternatives to participation in the formal economy more attractive; (6) variable responses to economic, cultural, and political changes; (7) the contribution of public policies to the formation of an urban underclass; and (8) the contentious character of culture. The Committee has commissioned review and research on the following subjects: (1) alternative opportunity structures; (2) the spatial mismatch hypothesis; (3) "demand side" theories and deteriorating relative earnings; (4) a cultural approach entailing social constructions of meaning; (5) discontinuities in job histories; (6) a large survey of poor and non-poor in Boston; and (7) an employers' survey conducted in Cook County (Illinois). A list of 25 references is appended. (AF)