Since the publication of the first edition of Learning by Doing, the authors have made presentations to tens of thousands of educators, served on dozens of panels to answer their questions, worked with several districts on a long-term ongoing basis to assist with their implementation of the professional learning community (PLC) concept, and participated in ongoing dialogue with educators on the allthingsplc.info website. This continuing work with teachers, principals, and central office staff from schools and districts throughout North America has given them a deeper understanding of the challenges educators face as they attempt to implement the professional learning community process in their organizations. This second edition attempts to draw upon that deeper understanding to provide educators with a more powerful tool for moving forward. Like the first edition, the second edition of Learning by Doing: A Handbook for Professional Learning Communities at Work helps educators close the knowing-doing gap as they transform their schools into professional learning communities (PLCs). This handbook is a guide for action that will: ¿ Help educators develop a common vocabulary and consistent understanding of key PLC concepts. ¿ Present a compelling argument that the implementation of PLC concepts will benefit students and educators alike. ¿ Help educators assess the current reality in their own schools and districts. ¿ Convince educators to take purposeful steps to develop their capacity to function as PLCs.