A case study of three high schools was conducted as the first phase of a 2-year study of comprehensive high schools' vocational course offerings and how they decide which students should be enrolled in them. The schools are similar in size and grade span and in the same labor market area; they belong to different school districts and serve different student populations. One school serves a racially and socioeconomically diverse group in a naturally integrated neighborhood, the second school serves a mostly middle- to upper middle-class White and Asian population, and the third school serves a student population nearly all Black or Hispanic, with a substantial proportion poor. Other differences in the schools included differences in the type and range of vocational programs, number of and expectations for the students who take the courses, organization and management style of the schools, morale of faculty and staff, and local traditions or history. At all three schools, the guidance and placement systems seem to concentrate on college-bound and severely troubled students, almost ignoring noncollege-bound, untroubled students. Although each of the schools offers a variety of vocational courses, none has a cohesive, comprehensive vocational program. At all three schools, the perception of vocational education was of poor teachers, poor equipment, poor students, and poor courses. The study concluded that a radical approach to high school reform that would involve a more fundamental reconstruction of the high school curriculum, blurring the distinction between academic and vocational subjects, should be investigated. (31 references.) (KC)