This study explores the determinants of urban unemployment in 30 major cities, particularly in the inner core slums among nonwhites and youth. Using data for 1960, a year of recession, and 1966, a year of prosperity, the author found that a factor which may be important under one set of economic conditions is not so in another cycle. Although unemployment in the nation dropped between the study years, many large cities did not experience a proportionate decrease in unemployment. This selective prosperity among cities and slums is examined and identified. The study's most surprising finding was probably that a high rate of crimes against property correlates with lower unemployment rates for minorities and slum dwellers, due to the fact that many disadvantaged persons view illegal activities as an alternative to no work or marginal jobs and therefore stop looking for regular employment. Racial discrimination was found to be a major factor in the high unemployment rates among nonwhites and slum dwellers, contributing to the seeking of illegal income opportunities. The author stresses that manpower training must be more closely linked to job placement to be of help to the urban disadvantaged. Policy recommendations derived from the findings are addressed primarily to the Federal Government but with important roles for State and local Governments. (MF)