Education Development Center, in conjunction with the Urban Mathematics Collaborative and Sunburst Corporations, is requesting funding for a conference to plan "Teaching and Schooling for a New Vision of Secondary Mathematics." The Geometric Supposer software will serve as a focus and exemplar for developing the conference themes. The conference will bring together representatives of the school restructuring movement, a range of secondary school mathematics educators, and mathematicians. The conference will address questions related to: the defining characteristics of a new vision of secondary mathematics instruction as exemplified by the use of the Supposers: the new roles and responsibilities required of teachers by these approaches: and the place of these experiences and approaches within the school restructuring movement. Recommendations for continued activity by participants will be the major conference outcome, and will be disseminated through a variety of vehicles. Cost-sharing is provided as 100% of the NSF award.