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. With recent progress in scanning techniques, including high resolution CT, NMR, and PET imaging of the brain, it has become possible to study and localize any brain area of interest. With the concomitant advances in computer technology, 3-dimensional reconstruction of deep seated lesions in stereotactic space is possible and the way is open for combined surgery with stereotactic precision and computer guided open resection. This type of open surgery in stereotactic space is already being developed in some centers with the aid of microsurgical, fiberoptic, and laser beam instrumentation. With these advances stereotactic techniques will rapidly become in tegrated into clinical neurosurgery. Stereotactics has become a metho dology which enables the surgeon to attack deep seated and subcortical small tumors. Neurosurgeons may abandon therapeutic nihilism, still frequently seen in glioma treatment, in the near future when stereotactic resection will be feasible and remaining tumor cells may be killed by adjuvant treatment modalities still in development."