This book discusses the fundamentals as well as modern approaches of immunology. As a branch of bio-medical science, immunology refers to the study of the immune system, its physiological functions, its chemical, physical, biological characteristics and the causes of its malfunction. There are various types of immunological studies like classical immunology, developmental immunology, theoretical immunology, diagnostic immunology, cancer immunology, etc. This text will trace the progress of this field and highlight some of its key concepts and applications. It will attempt to provide a comprehensive understanding of the multiple branches that fall under immunology and their importance. From theories to research to practical applications, case studies related to various topics of relevance to this subject have been included in this book. Students, immunologists, doctors, researchers and all interested in this area will find this book beneficial.