Peter Senge writes that learning organizations are places “where people continually expand their capacity to create the results they truly desire, where new and expansive patterns of thinking are nurtured, where collective aspiration is set free, and where people are continually learning how to learn together” (2006, p. 3). In this issue of JSD, you’ll read about learning schools. In these schools and systems, core elements of NSDC’s definition of professional learning come to life. As you read through the issue, starting with Stephanie Hirsh’s introduction to the definition (p. 10), you’ll see the connection between the concept of a learning organization and the high-quality professional development we hope to see in all schools and districts. At St. Johnsbury School in Vermont (p. 40), teachers