This chapter begins with a general outline of the nature and context of the Scottish Integrated Science scheme and its innovative characteristics. It describes how the teachers reacted to the innovative proposals. The chapter summarizes the findings, using a framework of 'costs' and 'rewards' to the teacher, and contrasts the goal of leading teachers to implement specific innovations with that of helping teachers to become self-critical decision makers about their own teaching. It explores ways in which support for innovation might be given to teachers that is sensitive to their own concerns and to classroom realities. An attempt was made to ensure the involvement of science teachers in the planning of the Integrated Science scheme through representation on the Working Party. Much of the curriculum planning of the last two decades has failed to take into account the nature of the cost and rewards associated with changing classroom practice.