Professor Russell's monograph takes as its thesis that all instances of hydrocephalus are caused by obstruction in the circulation of the cerebrospinal fluid. In a large series of cases studied personally by her, the cause of the obstruction was found in every instance. The material is presented on an etiologic basis, with carefully reasoned comments, illustrative case histories, exceptionally good photographs and reviews of relevant experimental data when available. The chapters deal successively with maldevelopments, gliosis of the aqueduct, inflammations, thrombosis of the dural sinuses and neoplasms. Then follows a section dealing with the anatomic effects of hydrocephalus per se on the central nervous system and its coverings. Of special interest is the excellent discussion on hydrocephalus following recovery from meningitis, particularly in view of recent success in the treatment of meningitis by antibiotics and sulfonamides. Russell also marshals convincing arguments that some instances of hydrocephalus previously regarded as "idiopathic"