For many years, the authors have been cotravelers on the journey to help educators improve their schools. As Dr. DuFour has focused on bringing the professional learning community process to life in schools, he has relied heavily on Dr. Marzano's vast research on effective teaching and effective leadership. Both have come to the conclusion that the best environment for great teaching and leading is a powerful PLC. In their first coauthored book, Dr. DuFour and Dr. Marzano have combined their passions to articulate how effective leaders foster continuous improvement at the district, school, and classroom levels. The book focuses on district leadership, principal leadership, and team leadership, and addresses how individual teachers can be most effective in leading students—by learning with colleagues how to implement the most promising pedagogy in their classrooms. The authors argue that no single person has all the knowledge, skills, and talent to lead a district, improve a school, or meet all the needs of every child in his or her classroom. Instead, it will take a collaborative effort and widely dispersed leadership to meet the challenges confronting schools.