This book comprises of ten chapters and it describes the origin, history, timeline, production and scope of immunoglobulins which are the central molecules of the immune system around which the field of immunology revolves. This book describes how the immune system responds to injuries and insults by foreign antigens (bacteria, viruses etc) and produces immunoglobulins, which then through various immune response mechanisms protect the body against pathogenic invasions. Further, it discusses how these antigens are involved in the differentiation and maturation of immune cells, how lymph nodes are involved in concentrating the antigens, how immunogenicity of an antigen is affected and how antigenicity of immunogens is related to the immune response. Classification of immunoglobulins and the organisation and expression of immunoglobulin genes is described separately. The antigen antibody interactions and antibody dependent cell mediated cytotoxicity are also discussed in separate chapters. The magic bullets or monoclonal antibodies, which have revolutionized the field of immunology, are described in greater detail, their production by hybridoma technology and the important role played by these antibodies in research, diagnostics and therapeutics is also discussed in the book. Lastly the immunodiagnostic techniques like radioimmunoassay (RIA), Enzyme Linked Immunosorbent Assay (ELISA), flowcytometry and their importance in the detection of various kinds of diseases like cancer, HIV-AIDS, tuberculosis, malaria, etc. are discussed in detail as well in the book. The book contains a large number of flow charts, diagrams, depictions and tables highlighting the properties, characteristic features, functions and roles played by these immunoglobulins in various fields of biosciences.