Part of the folk wisdom of teaching is that one really comes to understand a subject when one has to teach it to others. This article considers the ramifications of such a ‘simple truth’. Three key questions are explored: Why should preparing to teach provide such effective learning?, What does this suggest about the way teachers should organise learning in classrooms?, and Why does school learning not seem to reflect the conditions of learning that teachers found so effective. It is suggested that teachers should do more to recreate the circumstances surrounding their own intensive learning experiences for their students. A motto might be: ‘teacher, teach thyself, and then teach others by your example’.

Keywords: teaching, learning, teacher development, autodidactism, metacognition