Abstract
In this article we examine the teacher's role as a mediator of knowledge and cognitive learning in the classroom. We cite findings from the research areas of teacher effectiveness, teacher expertise, and curriculum knowledge. These data strongly support user‐friendly explicit methods of classroom teaching. We also discuss issues raised in conjunction with alternative conceptions of the teaching process. Finally, we note the importance of incorporating teacher effectiveness research findings into teacher education programmes, and of identifying the various misconceptions that have been used to criticise this body of information.