This essay discusses the immunohistochemistry method for identifying Epstein Barr Virus (EBV) in human tonsil tissue samples. It covers the fixation process using Formalin-Fixed Paraffin Embedded (FFPE) technique, antigen retrieval methods, choice of primary antibody, and the detection system. The essay also emphasizes the importance of using monoclonal antibodies for greater specificity in the antigen-antibody reaction.