The book examines in detail the structure and functions of the human immune system in normal and pathological conditions. The latest data on etiology, pathogenesis, clinic and pathomorphology of primary and secondary immunodeficiencies, autoimmune and allergic diseases are presented. The book describes the mechanism of action of immunotropic drugs and glucocorticoids, provides modern classifications and methods of treating immunopathological conditions. A large number of original drawings and diagrams are also contained.