When principals and teachers share leadership, teachers' working relationships with one another are stronger and student achievement is higher. District support for shared leadership fosters the development of professional communities. PLCs can be a powerful vehicle for facilitating instructional improvement and student learning, but without the guidance and support of principals, effective implementation is impossible. <b><i>Leverage</i></b> focuses on a series of high-leverage practices that, when taken by principals and coupled with highly effective Professional Learning Communities hold unlimited potential for our children. It provides research and evidence-based strategies that will be most effective and efficient in achieving the mission of schools—high levels of learning for all.