Encephalography is a procedure in which a series of properly exposed roentgenograms are made of the head in several positions in the erect posture within one hour following the removal of all the available cerebrospinal fluid and its replacement with air by the cisternal or lumbar route. Dandy (1918-1919) was the first to visualize the possibilities of this method, as well as to demonstrate the cerebral ventricles by the direct introduction of air into them. Bingel (1921-1923) pointed out the value of injections of air by the lumbar route. At about the same time, Martin and Uhler (1922) reported a series of cases in which this method had been of diagnostic value. Since the inception of encephalography many investigators have confirmed its value as a diagnostic procedure in establishing the character, localization and extent of cerebral lesions. TECHNIC The success of this procedure depends on the cooperation of neurologist, neurosurgeon