This project will develop a large-scale professional development strategy in mathematics and science to support pre-service and beginning K-12 teachers in mathematics and science. As part of the planning effort, the research team will formalize partnerships with major education organizations and engage in prototype development and feasibility research to develop models for courses, activities, and tools that will support the preparation of new teachers. The proposed professional development model would be most appropriate for college students in their junior and senior years or in post-baccalaureate programs, as well as for those in their first two years of teaching. The outcome of the planning grant will be a fully developed plan, with supporting research and evidence data, for the full scale implementation of the proposed effort.