The role of proprietary vocational schools in American postsecondary education and the way in which student financial aid is used are discussed. Proprietary vocational schools, organized as profit-seeking institutions, provide the bulk of American postsecondary vocational education. The average proprietary school is small and exists in a high-risk environment. Because student tuitions comprise the schools' sole source of revenue, they must be responsive to student and labor markets. Since federal student aid has largely accounted for the growth of the proprietary school industry, federal policies will likely exert a powerful effect on the schools' behavior. Proprietary schools' incentive structure apparently influences the way they package student aid, maximizing the use of grants, probably to aid recruiting and to the extent possible, minimizing loans. Because of proprietary schools' intense class schedule, work packaged as aid plays a relatively small part in student assistance. There is evidence that the schools' profit-seeking structure achieves certain efficiencies, not found in public schools, that carry benefits for students and the public. Information is presented on enrollments, program characteristics and costs, student job placement and earnings. (SW)