Immunosuppression in solid organ transplantation is experiencing a worldwide revival since new drugs are now available in the late-1990s and others are under development. In order to contribute to the design of future strategies, a critical approach of surrogate endpoints is given and long-term side effects are analyzed, together with the impact of non-compliance, quality-of-life and economical parameters. In this book, international specialists have set up the scientific rationale and provided new bases for further immunosuppressive strategies.