Richard Skolnik opens his Essentials of Global Health course, originally produced for Yale and Coursera, by laying out the basic vocabulary of the field: what counts as a global health issue versus a purely local one, and why the boundaries have blurred as diseases, funding, and policy now cross borders constantly. He walks through the main categories of actors involved, from national governments and multilateral bodies like the World Health Organization and World Bank to bilateral donors, NGOs, foundations, and private industry, explaining how each is organized and what role it plays in setting priorities or delivering care. The module is framed as an orientation lecture, setting up the concepts and cast of players that the rest of the course will return to in more depth. It stays at an introductory level, useful as a map of the field before the course moves into specific diseases and interventions.