MISE began partnering with four school districts - three in New Jersey and one in Pennsylvania in 1993. The success that the partners have had in improving instructional practice in science is anchored in the belief that to make lasting improvement in teaching and, consequently in learning, one must work systemically on multiple domains of the district and school culture at the same time. MISE invited four school districts to come together to build a professional community in science, a community which valued teacher expertise and invested in the continued professional learning for teachers, a community that worked together to improve teaching and learning in science. MISE worked with its partners to create their own professional communities , to build their capacity to support the continuous improvement of teaching, and to align their policies and resources with their shared vision of good practice.