This book will address the growing roles of epigenetics in disease pathogenesis, and review the contribution of epigenetic modifications to disease onset and progression. The roles that epigenetics plays in facilitating effects of the environment on allergy and immunologic diseases will be reviewed. The book is divided into three parts – the first is an introduction to epigenetics and the methods that have been developed to study epigenetics, the second addresses epigenetics in allergic diseases and the third part will cover epigenetics in autoimmune diseases. With the rapid expansion of knowledge of how genes are regulated and how this regulation affects disease phenotypes, this book will be attractive to experienced researchers as well as those just launching an epigenetics research program. It will also be of interest to allergist, immunologists, rheumatologists and dermatologist who are engaged in clinical practice as a resource for understanding the basis for personalized and precision medicine. For example, the role that epigenetics plays in the pathogenesis in various allergic and autoimmune disorders and how this determines disease phenotypes will be covered extensively in this book. This book will thus help fill the gap in available resources on epigenetics in allergy and autoimmune diseases.