Immunology is an interdisciplinary subject encompassing a number of other fields like microbiology, biochemistry, molecular biology, biotechnology, zoology, clinical medicine, pathology, etc. The approach towards the subject is changing gradually according to growing needs in the various other fields. Currently more emphasis is given to the molecular aspects of immunology. This has opened the floodgates towards the new approach for the treatment and diagnosis of many diseases including cancer. Bearing all these aspects in mind, apart from the conventional chapters, various new chapters like immunological synapse, molecular immunology, immunohistochemistry, tumour immunology, etc., have been included. Thus this book comprehensively covers all basic and advanced aspects of immunology in a simple manner in order to keep in pace with the modern developments in this field. It provides up-to-date information with necessary illustrations that will help students to understand the recent concepts in every area of immunology.