The Poincare Institute for Mathematics Education, led by Tufts University, in collaboration with TERC with and Dover, NH, School District as core partners, and partner districts in Massachusetts (Fitchburg, Leominster, Medford, Medway, and Somerville), New Hampshire (Dover, Sanborn, and Timberlane), and Maine (Portland), seeks to transform and improve the teaching and learning of mathematics in middle school and the connections between the elementary, middle, and high school curricula. The project's work will directly benefit 180 in-service and 24 new teachers and, each year, more than 2200 students. Building on successful NSF-funded collaborations between Tufts and TERC - the Fulcrum Institute, the Early Algebra, Early Arithmetic Project, and the Inquiry Project, the Partnership leverages expertise from mathematicians, physicists, educational researchers, and school districts to: (a) create graduate-level online courses on mathematical content, research in mathematics education, and mathematical knowledge for teaching, offered to three cohorts of in-service teachers (grades 5 to 9) from three states; (b) use algebra and the mathematics of functions and modeling for promoting coherence among topics in the mathematics curriculum; (c) implement permanent discussion forums where teachers plan, review (using video technology), and improve their lessons, drawing upon the critical mathematical topics and issues of learning and teaching; (d) strengthen and expand partnerships with schools by preparing teachers and researchers in Tufts' graduate programs in Mathematics and Education, through internships with teacher leaders and participation in educational research; (e) conduct research on teacher development and student learning; (f) support school district's efforts to improve their mathematics curriculum; and (g) disseminate a teacher development model for adoption by other university-school partnerships. The project rests on the premise that to improve students' learning one needs to broaden and deepen teachers' understanding of mathematics, of how children think and learn, and of mathematics knowledge for teaching. The Poincare Institute offers an interdisciplinary, research-based model for introducing a deeper, integrated approach to mathematics in districts where minority and under-privileged students typically underperform. The courses, materials, and examples of effective teaching are free, open-source, cross-platform modules that universities and schools can use and modify under Creative Commons licensing. The partnership also contributes to the preparation of teachers, research students, and post-doctoral fellows.