Leadership is an ill-defined domain, drowning in abstract theories and models of expertise. School leadership suffers from this lack of a satisfactory and useful definition of leadership, and has of late been drawn in to generic approaches to school improvement which have left the workforce feeling anything but `well led'. How do we put `substance' back in to school leadership? This book draws on the lessons of cognitive science and explores the specific things that school leaders do, arguing for a notion of school leadership rooted in the realities of leaders' daily experiences. It presents a case for how school leaders can develop their expertise and, in doing so, places domain-specific knowledge at the heart of school improvement efforts.