The complexity of mathematics teaching involving both cognitive and sociosystemic factors makes development problematic. Examples from research into teaching reveal factors in complexity and ways in which inquiry between teachers and didacticians can foster deeper ways of knowing in the developmental community. Research is seen as the basis of an inquiry process which develops inquiry in mathematics teaching as both a tool for teaching and a way of being for all learners. Theoretical discussion on the concepts of inquiry and community and their relation to development leads to consideration of approaches in which mathematics teaching development is the object of a design process. Tensions between learning theory and proposals for developmental practice are revealed and addressed. Research that is designed to create and study inquiry communities is introduced. [For complete proceedings, see ED489178.]