The volume is devoted to the biliary system, liver, pancreas, and spleen. The first part examines the laboratory and diagnostic capabilities of instrumental methods, as well as the use of certain invasive methods for alternative treatment. Four sections present the etiology, pathogenesis, clinical features, diagnosis and differential diagnosis, prognosis, conservative and surgical treatment of diseases of these organs. Special attention is paid to the treatment options for portal hypertension. The current possibilities for diagnosis and treatment of diseases of the biliary system, liver, pancreas, and spleen are reflected.