With Circular H.S.1 1972/73, the Ministry of Education directed Ontario's secondary schools to provide an increased range of course offerings and to allow students as much freedom as possible to choose their own courses. To identify the effects of the individualized "credit system" established by this controversial circular, a number of studies were conducted during the 1972-73 school year. This booklet reports on a study of student participation in school decision-making. Data were gathered from intensive case studies of two schools (one "traditional" and one "free") and from questionnaires completed by 2,860 students, 846 teachers, and 843 student government members from a representative sample of 37 Ontario secondary schools. In their analysis, the authors devote particular attention to examining the need for student participation in decision-making, patterns of influence in secondary schools, student government effectiveness, student government as a pedagogical tool, and the "house system" of school organization. (JG)