The aim of this book is to try to find frameworks for how to solve ethical dilemmas within One Health approaches. This first chapter introduces One Health approaches, their scope and history arguing that ethics have been neglected within these. A brief introduction in the field of ethics is made with the aim of distinguishing some important concepts that will appear in forthcoming chapters. Four ethical trends are introduced and briefly mentioned how they influence this work. The trends are expanding ethics, questioning the individualistic take, pluralism, and constructivism. Then there follows a presentation of the structure of the book with the different topics covered. Finally, three ethical cases will be presented which will follow the reader through Chaps. 4 to 7 as an analytical tool to understand the differences in the ethical viewpoints presented and discussed. These real-world dilemmas cover important aspects of One Health approaches.