Precision Health and Medicine (PHM) represents a paradigm shift in healthcare, integrating interdisciplinary approaches to individualized patient care. The book is divided into three parts. Part I lays the groundwork, distinguishing PHM from traditional medicine and highlighting the roles of the various 'omics' disciplines as well as data science/artificial intelligence in PHM. In Part II, the focus shifts to specific applications of PHM, showcasing its therapeutical potential across diverse medical domains. Part III is forward-looking, considering social, ethical and legal issues in the implementation of PHM. It also reflects on the future of PHM, speculating on developments and challenges while outlining pathways for clinicians to integrate precision approaches into practice. We hope this book can serve as a reference guide to introduce healthcare practitioners to what PHM is, why PHM is important, where PHM can be applied, and how PHM will affect clinical medicine.