Leprosy is the cause of the commonest peripheral neuropathy. The predilection of Mycobacterium leprae for nerve tissue accounts for the clinical features that are most dreaded and most characteristic of the disease. Were it not for the progressive destruction of peripheral nerve trunks and the consequences of this, leprosy would largely remain a cutaneous condition of cosmetically unsightly hypopigmented or erythematous areas and aggregations of nodular thickenings. The neurologic damage in leprosy is confined to postganglionic changes. The central nervous system is protected, although rarely in experimental situations organisms have been reported in cerebral tissues.