Countries throughout the world are faced with the problem of adjusting school mathematics curricula in an attempt to match rapid changes in society, technology and educational systems. The ICMI Study is intended to help those who wish to form a vision of what school mathematics might be in the 1990's and to work towards the fulfilment of goals. In doing this it will be guided by the experiences of the past thirty years, which have taught us that what is desirable might not be attainable, and that goals must be set which acknowledge the existence of constraints. The Study seeks to identify key issues and basic questions within mathematics education, to propose and comment upon alternative strategies, and to provide a stimulus for more detailed, less general discussions, within more limited geographical and social contexts. The text is based upon an international symposium held in Kuwait in February, 1986 and attended by selected mathematics educators drawn from all parts of the world.