This report looks at the individuals who were enrolled in postsecondary school during the 1990-1991 school year and the costs and financing of their education. Using data from the Wave 5 component of the 1990 Survey of Income and Program Participation (SIPP), the report examines patterns of school enrollment, education costs, financial aid, and the associated characteristics of postsecondary students in the U.S. The report includes those enrolled in two-year and four-year colleges as well as vocational, technical, and business schools. The tabulations show the numbers of high school graduates enrolled in postsecondary institutions by a variety of demographic, social, and economic characteristics. Other tabulations show the average costs, financial aid received, net costs, and numbers of aid recipients by level of enrollment. These tabulations are crossed by gender, family income, race/ethnicity, and student dependency status. Appendices provide tabulations referring to the school year 1987-1988, an overview of the SIPP program, definitions and explanations, an analysis of the source and accuracy of the estimates and the data quality, and a copy of the questionnaire. The report's highlights indicate that the average total cost of schooling was $2,653 per student, and that among those students who received some kind of financial aid, about 75 percent of their costs were covered. (JDD)