Our final point follows from these two and relates to curriculum and professional development. Our study has shown the complexity, richness and sophistication of history teachers' thinking and the skill, sensitivity and range of their practice. It follows from this that attempts to develop, extend and improve classroom practice need to take seriously the detailed professional knowledge which history teachers already possess and deploy. Programmes of curriculum reform, and the supporting professional development, which do not do this will simply fail because they do not appreciate the complexity already being actively managed by history teachers. Generic professional development, grounded on deficit model perceptions of what teachers are 'failing' to do, are unlikely to build on the things which are being done with great skill and sophistication. Worse, for those promoting change, if the professional development fails, the curriculum reform it supports will founder. What this study demonstrates is that history teachers have the knowledge and skill to implement reform programmes of great sophistication; equally, they have the knowledge and skill - perhaps fortunately to thwart ill-conceived innovation. This knowledge and skill is something to be celebrated, certainly, but successful professional and curriculum development needs to understand and take account of it if significant development is to succeed.