The issue of underemployment (a condition characterized by inadequate hours, inadequate income, and/or inadequate use of skills) is explored in this monograph. The methodology and vocabulary of underemployment are first examined, including a definition synthesis of hours worked, skill utilization, and compensation. The second section provides statistical measures of the incidence of underemployment for the following categories: part-time underemployed, and populations at risk--farmworkers, women, youth, minorities, and college graduates. Among the causes of underemployment described in the third section are the effects of automation, trade deficits and increasing foreign competition, high military spending, reduced Federal spending for retraining and enforcement of equal rights, increased employment of women, and declining union membership. Suggestions for career assistance specific to each type of underemployment are made. For those employed below skill level, recommendations are made for improved labor market information and public employment services, and changes in the relationship of schooling and work. The part-time underemployed could benefit from national commitment to full employment, changes in work attitudes, job search skill training, and job creation. Employability programs and comparable worth legislation are suggested to aid the low-income underemployed. Finally, from two scenarios about the future of work the author draws implications for underemployment and predicts future directions for skill utilization and pay equity. A summary of positive and negative trends leads to a conclusion of guarded optimism that the problems of underemployment are solvable. (SK)