The present monograph will concern itself with those disorders of the endocrine system, either associated with destruction, interference with function or hyper- function, which are considered to be due to auto-immune processes. Endocrinopathies Non-endocrine auto-immune disorders associated with the endocrinopathies Graves' (Basedow's, Parry's) disease Pernicious anaemia Hashimoto's thyroiditis Vitiligo Idiopathic Addison's disease Myaesthenia gravis Insulinopenic diabetes mellitus Sjogren's syndrome Auto-immune oophoritis and orchitis Rheumatoid arthritis Auto-immune hypoparathyroidism Idiopathic thrombocytopenic purpura Auto-immune hypophysitis Chronic active hepatitis Possibly some cases of infertility Primary biliary cirrhosis due to anti-sperm antibodies Reproduced with permission from Volpe (1977) The above table indicates those organ-specific endocrinopathies considered to be due to auto-immune factors, as well as those non-endocrine, organ-specific auto-immune disorders which may be associated with them (Volpe 1977). It is evident that such disorders, occurring without any obvious external cause, raise the very elementary question of how immune processes directed against self- constituents could be initiated. Generally, of course, the immune system acts as a regulatory and defence mechanism, and disorders of auto-immunity represent breakdowns in this regulatory system. The following chapters will be concerned with the individual components ofthe endocrine system so affected by auto-immune processes; it will first be necessary to provide an initial chapter for the purpose of summarizing some general principles of immunology, in order to place the immune disorders of the endocrine system in context.