Book excerpt: Human health depends on the health of the planet. Earth’s natural systems—the air, the water, the biodiversity, the climate—are our life support systems. Yet climate change, biodiversity loss, scarcity of land and freshwater, pollution and other threats are degrading these systems. The emerging field of planetary health aims to understand how these changes threaten our health and how to protect ourselves and the rest of the biosphere. Planetary Health: Protecting Nature to Protect Ourselves provides a readable introduction to this new paradigm. With an interdisciplinary approach, the book addresses a wide range of health impacts felt in the Anthropocene, including food and nutrition, infectious disease, non-communicable disease, dislocation and conflict, and mental health. It also presents strategies to combat environmental changes and its ill-effects, such as controlling toxic exposures, investing in clean energy, improving urban design, and more. Chapters are authored by widely recognized experts. The result is a comprehensive and optimistic overview of a growing field that is being adopted by researchers and universities around the world. Students of public health will gain a solid grounding in the new challenges their profession must confront, while those in the environmental sciences, agriculture, the design professions, and other fields will become familiar with the human consequences of planetary changes. Understanding how our changing environment affects our health is increasingly critical to a variety of disciplines and professions. Planetary Health is the definitive guide to this vital field.