Editorial. The question of 'how teachers learn' is important because answers to this question may result in recommendatons for the improvement of both initial teacher education and the further professional development of teachers. All five articles in the special issue address this question.

The purpose of this paper is to explore how experienced teachers learn informally, and more specifically, how they learn through the activities they undertake when teaching classes. Regarding these activities we studied four aspects: behaviour, cognition, motivation and emotion. During one year, data …