Research is almost unanimous in finding that the principal's role has typically been crucial to successful schools yet many practices are too simple for the complexity of dealing with hyper-turbulence facing school leaders these days. This book was written to an international audience in order to provide a state-of-the-evidence description of what is missing about successful school leadership in a hyper-turbulent environment. It was anticipated that such a description would be of some immediate use and guidance to those already in leadership positions, those aspiring to be school leaders and those with responsibilities for leading schools in a changing external context. It is also hoped that the book will helped to clarify the most important questions for inquiry and offer conceptual lenses on key variables of interest to school leaders who lead schools in a changing contexts where global forces are defining, changing, and perhaps even diminishing the role of school leaders as prime leaders.