More children born today will survive to adulthood than at any time in history. It is now time to emphasize health and development in middle childhood and adolescence—developmental phases that are critical to health in adulthood and the next generation. Child and Adolescent Health and Development explores the benefits that accrue from sustained and targeted interventions across the first two decades of life. The volume outlines the investment case for effective, costed, and scalable interventions for low-resource settings, emphasizing the cross-sectoral role of education. This evidence base can guide policy makers in prioritizing actions to promote survival, health, cognition, and physical growth throughout childhood and adolescence.