The early chapters of the book provide a broad overview of the immune system and its functioning. The subsequent chapters present the importance of discriminating self from non-self through pattern recognition receptors (PRRs), structure and function of antibodies, major histocompatabilitycomplex, antigen receptors of the adaptive immune system, cellular interactions that lead to activation of T and B lymphocytes, immune responses against various categories of pathogens, and manipulation of the immune system by vaccination and various vaccine strategies. The book also includesclinically significant areas and hypersensitivity states including allergy, immunodeficiency disorders, transplantation, and tumor immunology. There is also a special emphasis on the HIV/AIDS pandemic against which efforts are on at a massive scale. Tolerance and autoimmunity have also been linkedfor a better understanding of the mechanisms that could lead to autoimmune diseases.An additional feature of the book is the inclusion of various techniques, immunoassays, and experimental systems provided in the appendix. ELISA and other immunological techniques like agglutination and precipitation having wide ranging applications have also been included in the book.