ENResearch is clear: School leadership quality matters. However, our knowledge of effective school leadership remains limited in at least three substantial ways. First, our understanding of school leadership effectiveness generally and school principal effectiveness specifically is limited to Western contexts, primarily North America and western European ones. Second, even in the confines of Western research and context, there has been relatively little specific focus on effectively leading low-performing schools. Third, even the conceptualization of leadership—do we mean the school principal, an administrative team, or a broader school leadership team—is a key factor in how we define and respond to the challenge of leading in low-performing schools. This book advances discussion and disseminates knowledge and global perspectives on what school leadership looks like, how it is enacted and under what circumstances, and when or where lessons might be portable.