Increasingly, it is not just the state that determines the content, delivery, and governance of education. The influence of external actors has been growing, but the boundaries between internal and external have become blurred and their partnerships have become more complex. This book considers how schooling systems are being influenced by the rise of external actors, including private companies, non-governmental organisations, parent organisations, philanthropies, and international assessment frameworks. It explores how the public, private, and third sectors are becoming increasingly intertwined. Introducing new theoretical frameworks, it examines diverse sites - including Cambodia, Israel, Poland, Chile, Australia, Brazil, and the United States - to study the role of policies, institutions, and contextual factors shaping the changing relationships between those seeking to influence schooling.