The Canadian researcher Peter Coleman argues that the best sources of evidence on good teachers are pupils.2 This view might be contested by other researchers who have brought a sophistication of insight into what teachers do and have written insightfully on the subject. There is now an extensive literature on the subject,3 but however good the objective observation, it has to be taken together with the subjective, introspective evidence of those who live day to day with teachers and see them in their darkest, as well as their brightest, periods.