When talking with students, teachers, educational administrators, or professors of education about good teachers, it is common to hear teachers commended as "imaginative". The kinds of things they do in class are frequently -- to use Barrow's (I990) joint criteria for imaginativeness -- unusual and effective. Such teachers show a flexibility of mind that enables them to present a subject in a new and engaging way, a way that enables students to understand it better and also to take pleasure from the learning. Given the frequency with which, in informal discussion, imagination is identified as a crucial feature of good teaching, it is surprising to find it almost totally ignored in research on teaching effectiveness. (In a review of such research, O'Neil [1988] identifies twenty "research factors", but "imagination" is not among them. Similarly, Porter and Brophy's [ 1988] review and synthesis of research on "good teaching" also ignores imagination.) This is no doubt in part due to the difficulty dominant research methods have in coming to grips with imagination, but it would be a great pity if its virtual absence in empirical research should encourage us to focus on the kinds of behavioural repertoires prominent in that research and ignore something so obviously central to good teaching as imagination. There is something in this of the old joke about looking for a lost key on the clean pavement under the bright street lamp because it is easy to see there, even though the key was dropped in the long grass further down the street where there is no light. Even though this book may occasionally seem to be feeling its way through tangles, it is at least, I think, looking in the right place for keys to effective teaching.