In many schools across America, teachers enter their classrooms each morning only to close the door and teach with little to no peer interaction. Working closely with several schools, the Center for Teaching Quality sought to address this culture of isolation, as well as to reduce the attrition rate among teachers, by initiating professional learning communities (PLCs), groups committed to continuous improvement through shared values and reflection. Working with their peers, teachers in PLCs collect and analyze classroom data, share best practices, and make instructional decisions as a team. Together, they engage in deeper learning as teaching professionals to better meet the needs of their students. This document is a best policies and practices guide for promoting teacher leadership through PLCs. The report also contains embedded podcasts. (Contains 8 endnotes.) [This report was made possible by the Center for Teaching Quality's Achieving School Success through Empowering Teachers (ASSET) Initiative with funding from the Wachovia Foundation.] [This report was made possible through the Achieving School Success through Empowering Teachers (ASSET) Initiative with funding from the Wachovia Foundation.]