This introductory chapter outlines the rationale for this book on evidence-based policy making and practice in Africa and sets the scene for the chapters that follow. The book takes a policy-maker, not a researcher perspective, and is concerned with how the use of evidence by policy makers and practitioners (project/programme managers) can be supported. The book documents eight African experiences in using evidence, from Benin, Ghana, Uganda, Kenya, South Africa and the ECOWAS region (i.e. West Africa). The chapter gives a brief contextual overview of the five countries from which the case studies in the book are drawn, locating the cases within their context. The research methodology is based on case studies and a realist approach to evaluation research. The case studies cover evidence generated through evaluation, research, research synthesis and the involvement of civil society. However, the book does not focus on the evidence itself but on how interventions that promote use played out and how they influenced individuals, organisations and systems, building capability or motivation to use evidence, and creating opportunities to use evidence. The cases show how these led to policy outcomes. The chapter briefly introduces the analytical framework and outlines the structure of the book.