This volume provides the theory and research on which Elizabeth Cohen's ""Designing Groupwork: Strategies for the Heterogeneous Classroom"" (1994), was based. It documents, with systematic data collection and analysis, how it is possible to abolish ability grouping without sacrificing the intellectual challenge of the curriculum. This illustration of the practical application of sociological theory and research strategies shows how they can be utilized in reconstructing classrooms to simultaneously achieve goals of equity and development of higher order thinking. The innovation of this approach, Complex Instruction (CI), has a systematic knowledge base that permits examination of implementation, staff development, equal-status interaction, and outcomes of achievement and cognitive development. The work of this group of researchers is testimony to the potential that sociological theory and research have for the field of education.