This is the most comprehensive review of the idiotypic network available. All the current knowledge of idiotypes of the various antibodies is incorporated in this volume. The pathogenic role of idiotypes in autoimmunity and cancer is reviewed in depth. The therapeutic part focusses on harnessing anti-idiotypes for treating autoimmunological disorders, and on the employment of idiotypes for vaccines in cancer and infectious diseases, as well as explaining the manipulation of the idiotypic network in autoimmunity and cancer idiotypes and vaccines.