This book is divided into eleven chapters. Chapters 1, 2 and 3 present analyses of the concepts of public health, sustainability and policy change. Chapters 4 and 5 describe the stakeholder analysis and national health accounts frameworks. These chapters determine the attributes, characteristics and other features of these concepts and frameworks. The aim is to improve general clarity and understanding of these concepts and frameworks that contribute to the Sustainability Impact Assessment framework and the case study methodological approach that exemplifies its role in sustainability assessment of policy change in immunization systems. Chapter 6 outlines the Sustainability Impact Assessment framework itself, setting out the steps involved in a typical SIA with examples of methodologies used in the case study. Chapter 7 describes the case study methodological approach including its rationale and components. Chapter 8 outlines the application context of the case study with emphasis on the country's immunization system. Chapters 9 and 10 describe the application scenarios of the methodological approach, detailing the stakeholder analysis and resource map assessment processes. The summary and conclusions of the book are provided in Chapter 11. This chapter reviews the contributions of the Sustainability Impact Assessment framework and case study methodological approach, providing additional discussion of relevant issues and some directions for future work.