First published in 1990. This important new text covers a wide area of thymology in both the theoretical and practical aspects. In view of current information, a crucial role of endocrine thymus is presented in the creation, maintenance, and senescence of neuro-endocrine-immune homeostasis. In particular, mechanisms are described (which are basically responsible for the T cell maturation and selection) for the hierarchic organization of the immune system and its thymic dependent immune competence in terms of tolerance and immunity. A detailed presentation of the structure and biological properties of a number of well-defined thymic hormones is included. Their clinical applications and results obtained in inherited or acquired immunodeficiencies and in neoplasmic diseases are also reviewed on the grounds of numerous representative clinical trials. A perspective and potential scope of immunorestorative therapy and prevention with thymic hormones and other thymomimetic drugs are outlined. Researchers, practitioners, and students will find this book to be a useful and essential source of information.