This research report offers a theoretical frame for examining recent instructional improvement efforts. First, it develops a theoretical view of instruction and an analysis of the environments of instruction. It analyzes the relations between instruction and its environments and the circumstances under which intervenors must operate. The report discusses the problems and possibilities for intervention, offering an instructional theoretical frame. It develops an interactive model of instruction to analyze both teaching and efforts to improve teaching. The report elaborates on this split-level frame as it goes, drawing out implications for understanding instruction, instructional improvement, and research on the two. It concludes by summarizing the ideas and distinguishing them from other approaches to understanding and studying school improvement. Section 1, "Instruction," focuses on the interactions among teachers and students around educational material, discussing issues related to instructional capacity. Section 2, "Implications for Intervention and Research," examines comprehensiveness and intervention, teachers' unique roles, and teachers' opportunities to learn. Section 3, "Instruction and its Environments," focuses on schools, system organization, coordination of instruction, professional norms, resources for professional education, professional learning, the issue-attention cycle, and society and culture. Section 4, "Intervention," discusses design, specification, and development. Section 5, "Enactment," discusses relationships between intervenors and enactors. Implications for intervention and research are noted. (SM)