Richard Skolnik, lecturer at Yale and author of a leading global health textbook, closes out his Essentials of Global Health course by looking ahead at what will strain public health systems in coming decades. He walks through demographic shifts, the rising burden of noncommunicable disease alongside persistent infectious threats, climate change, and the strain of aging populations in both rich and poor countries. The lecture argues that science and technology alone will not be enough, and that collective action among governments, health systems, and communities is what determines whether new tools actually reduce disease and death. Skolnik draws on examples from his course's earlier case studies to show how these challenges connect to financing, workforce shortages, and political will. It is a summary lecture, pitched at students who have followed the full course, but clear enough to stand on its own as an overview of where global health is headed.