Our planet is amid some of the most complex environmental and development challenges in its history. As a conservation ecologist working with the United Nations Environment Programme, and previously with the United States Agency for International Development and the World Wildlife Fund, I have witnessed first-hand the multiple impacts of biodiversity loss, pollution, and climate change on the health of all species, including humans. For example, in Southern Africa the degradation of river basins, particularly the forested areas in upstream headwaters, has led to downstream die-offs of important species and contributed to disease in aquatic species consumed by humans, with human health and nutrition implications. These complex interactions of nature, animals, plants, and people, while not always easily understood, have important consequences for our ability to thrive on the one planet we all call home.

Many have come to recognise that human health is inextricably linked to the health of other animals and the planet. One Health is a policy approach based on recognition of this principle – that you cannot have healthy people in an unhealthy environment and that the health of humans, animals, and ecosystems are deeply intertwined. Addressing one aspect without considering the others will only lead to incomplete or unsustainable solutions.

One Health as a theory has existed since at least 2002, and probably much longer, but has taken on more prominence since the onset of COVID-19. It is being used as a premise in new international frameworks and agreements, including the Kunming–Montreal Global Biodiversity Framework and the International Agreement on Pandemic Prevention, Preparedness and Response currently under development, by multiple international organisations, and by various governments around the world. One Health offers various conceptual benefits, including governing for public health in a way that simultaneously protects the natural environments that we rely on. The practical benefits of One Health include the mobilisation of multiple governance sectors and the advancement of multidisciplinary collaboration. The potential of a One Health framework is immense. It could change the way we govern our own relationship with the natural world and could lead to health being considered as a matter of social justice.

The One Health framework, however, is still developing, and the limits of the approach as currently adopted continue to be revealed. For example, the framework, and its development and utilisation, still fall heavily within the realm of public and animal health and remain inherently anthropocentric. Wild animal, plant, and ecosystem perspectives are often neglected, particularly where multispecies communities are the centre of potential disease spread. In general, the many benefits of nature for health and well-being are overlooked in favour of a narrower focus on eradicating specific zoonotic diseases and antimicrobial resistance. Institutional silos and barriers between human, animal, and environmental disciplines persist. Additionally, and prominently for the purpose of this book, One Health has not been considered within a law and policy context on a broad scale. The need to better develop a legal, policy, and governance grounding for One Health was the subject of several plenary sessions at the recent 8th World One Health Congress (2024, Cape Town, South Africa), and was helpfully explored by some of the authors of this book in their panel on ‘Science Policy Interface – One Health and the Law: Existing Frameworks, Intersections and Future Pathways’.

Considering this need, this book aims to give the theoretical paradigm of One Health a grounding in law and governance. It discusses how One Health may be institutionalised in a productive, just, and effective way, throughout governance and legal structures, to achieve a more holistic accounting of its purpose. The authors explore and analyse the ways that One Health is already embedded in law and policy; consider what One Health frameworks can learn from, and contribute to, other legal theories, concepts, and practice; and map a path forward for a One Health framework in law and policy.

Because the potential of a One Health approach is so great, the promise offered by this book is similarly important. It offers analysis and frameworks which, if implemented, would enable a better adoption of One Health, one that is truer to its holistic and systemic underlying principles. In this respect, I am grateful to the editors for putting together this work to further advance practical applications of a true One Health approach.

Doreen Robinson