Most research into work hours over the past thirty years has focused on explanations for differences among individuals in their work behavior. There has been little analysis of changes in work hours over time. The purpose of this research is to undertake a detailed examination of hours of work since 1975 and to do so with sufficiently disaggregated data to identify differences in the movements of work hours among various types of workers. Since the late 1970s, relative wages have become more unequal. It is important to determine whether this development in the wage structure has been associated with changes in work behavior. To what extent has the growing inequality in earning been the product of the conversion of full-time, full-year, jobs into part-time jobs or through greater unemployment into part- year jobs? This project will provide detailed analysis of the relationship over these years between work behavior and wage rates. The principal source of data will be the March demographic files of the Current Population Survey which, since the 1976 Survey, provide information on the hours worked and weeks worked of respondents.