Great teachers, with the right policy supports, are the ideal agents of meaningful and sustainable change in the most challenged schools. Accomplished and effective teachers help students learn at high levels. They also spread their expertise throughout the school on behalf of all students. This report lays out compelling evidence about the actions required to identify and develop teachers and to recruit and retain them for high needs classrooms. This report also presents one union's commitment to advocate for principled changes in the status quo--signaling its determination to break ground for new teaching policy partnerships. It's time for policymakers and education leaders, including teachers, to strike agreement on a balanced approach to closing student achievement gaps--an agreement that recognizes the tight correlation among school leadership, working conditions, and teacher effectiveness. (Contains 80 endnotes.)