Therapeutic antibody engineering characterizes one of the emerging areas in medical and pharmaceutical industry. Currently, there are several monoclonal antibodies available in the market. These therapeutic antibodies are the second largest biopharmaceutical products category after vaccines. Antibodies have been engineered by a variety of methods to suit a particular therapeutic use. Hence, there is a need to understand thoroughly the structural and functional characteristics of antibody and the antibody engineering for the generation and optimization of therapeutic antibodies.