This volume, part of the Junior High School Transition Study, reports on findings regarding one of five areas of interest in the study. Questions being addressed are: (1) How do students participate in, and respond to, junior high school instruction? (2) Do students respond differently in different circumstances? and (3) Are these differences, if any, related to the success of students' transition to junior high school? The data base for this report includes case descriptions of 24 target students whose progress was followed from their sixth-grade classes in elementary school to their seventh-grade classes in junior high school. The first chapter provides an introduction to the study, part of the Ecological Perspectives for Successful Schooling Practice project. Findings are reported in chapter 2, as are the four criteria for judging students' success in transition in chapter 3. The fourth chapter details research methodology, study participants, and data collection and analysis. Fifteen tables accompany the text. (JM)