"The Learning Principal" is an eight-page newsletter published eight times a year. It focuses on the important and unique work of school principals. This issue includes: (1) Landmark Study Examines U.S. Professional Learning: Findings Point the Way to Improving Student Achievement (Stephanie Hirsh); (2) School Leadership: Q&A: Teachers Encouraged to Lead Their Own Professional Learning (Valerie von Frank); (3) Focus on NSDC's Standards: Become a Martian Anthropologist (Pat Roy); and (4) NSDC Tool: Defining Effective Professional Learning. (Individual articles contain references.)