Various textbooks on stereotactic neurosurgery have been published during the last few years (Riechert 1980, Schaltenbrand and Walker 1982, Spiegel 1982), all of them dealing with functional stereo tactics as the major subject in the field. Diagnostic and therapeutic stereotactic interventions are only briefly described, whereas localization techniques are not yet mentioned. Since 1980, however, an increasing number of reports has been published on CT guided and computer monitored stereotactic performances which enable the surgeon to combine diagnostic and therapeutic efforts in one session....