The past decade has been a productive era for classroom research. Recent investigations have yielded useful concepts for thinking about classrooms and about facilitating achievement. Research findings and concepts provide a way of considering classroom instruction, but they are not rules for classroom behavior. Some teachers believe (and behave accordingly) that they have little effect on students' learning. In fact, many teachers cannot simply and directly explain what they attempt to accomplish in their classrooms. Teacher training institutions need to give more attention to how their students perceive the role of the teacher and help teacher candidates develop a coherent teaching philosophy before they enter the classroom. Teachers who are confused about their role and goals and who hold low expectations for their classroom performance are unlikely to positively affect student learning and development. Recent research provides clear evidence that teachers do have important effects on students' performance. Furthermore, these studies provide important concepts for thinking about classroom teaching. This paper discusses research on: (1) teacher expectations; (2) teacher effectiveness (active teaching); and (3) classroom management, and the policy implications of each. (JMK)