Although there are a million reasons why some schools do not work, there is one thing that Breakthrough High Schools (BTHS) have in common: a principal who has a focused vision that is based on the needs of his or her school and district and an ability to rally the troops and move the school away from the herd. The principal's ability to carefully implement professional development with the local and professional communities makes all the difference in BTHS. In this article, the author discusses how BTHS principals create meaningful professional development, assess professional development, and determine appropriate measures for success.