The book contains advanced information about different immune techniques like Immunodiffusion, Immuno electrophoresis, immunofluorescence, agglutination, RIA, ELISA, Mab etc. and is useful for students in UG and PG levels. It narrates a general concept about different immunological techniques, explaining about different immune techniques and their application in different fields of applied Zoology and Biotechnology. We have tried to cover the basic concept of all immune techniques relating to their application in different fields especially in the field of disease diagnosis and treatment. The book also explains diagnostic techniques used in COVID. We have made a serious attempt to simplify the complicated language of immunology into a simple and understandable version.