Antigen processing is a biological process that prepares antigens for the presentation to special cells in the immune system called T lymphocytes. In , expert researchers in the field provide a comprehensive set of protocols for studying presentation of antigens produced in the standard processing pathways for MHC class I and class II molecules. The chapters follow chronology of intracellular processing events, ending with recognition of peptide-MHC complexes at the cell surface by T lymphocytes. Written in the highly successful series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and key tips on troubleshooting and avoiding known pitfalls. Authoritative and practical, is designed for beginners and experts interested in studying antigen processing.