A state-of-the-art reference for transplantation specialists, gastroenterologists, immunologists, surgeons, and hepatologists. It covers the topics: diagnosis of acute rejection, relevance of histological findings for the diagnosis, frequency of acute rejection, potential risk factors for the development of acute rejection, influence of HLA-compatibility on acute rejection, course without and after cessation of basic immunosuppression and tolerance, hyperacute rejection, and developments to improve the operation technique in the animal experiment.