This collection of reflective, critical, philosophical, and practical chapters represents the authors 60 years as a veterinarian, ethologist, and bioethicist. The rising incidence of zoonotic diseases from farmed animals and wildlife in the expanding human population and so-called reverse zoonoses where humans are infecting other species are existential concerns. These concerns are linked with anthropogenic climate change and our impact on ecosystems which threaten biodiversity and the health and future of Homo sapiens and many other species. These interconnected issues are examined in this book, broadening the scope and agenda of what is currently more narrowly practiced as preventive medicine. The author calls for greater emphasis on holistic preventive health-care maintenance in response to the escalating costs of human and companion animal health problems, the welfare of factory farmed animals, and endangered status of many wild species. Our species now faces a complex existential crisis that must be addressed in an interdisciplinary way, because there are multiple contributing factors; factors that call for the insights of science and bioethics. Fearlessly tackling contentious issues and 'wicked problems,' Dr Michael W. Fox offers an integrated perspective of what One Health looks like on the ground.