1: Introduction.- I. Stereotaxy in Experimental Brain Research.- A. Clarke's Instrument.- B. Clarke's Idea.- II. Stereotaxy in Man.- A. Functional Stereotactics.- B. Mass Lesions Stereotactics.- C. Stereotactic Localization.- III. Stereotactic Methodology.- IV. Integration of Stereotactics in Clinical Neurosurgery.- 2: Stereotactic Principles.- I. Development.- II. Definition.- III. Stereotactic Atlasses.- IV. Invisible and Visible Targets.- V. Preparation of the Stereotactic Intervention.- A. The Positioning of the Target with X-ray Pictures.- 1. The Invisible Target.- 2. The Visible Target.- B. The Positioning of the Target with Computerized Tomography.- C. Calculation of Target Point.- D. The Stereotactic Intervention.- 1. Talairach System.- 2. Riechert-Mundinger System.- 3. Leksell System.- 4. Todd-Wells System.- 5. The Ideal Stereotactic System.- E. Stereotactically Guided Instruments.- 1. Electrode.- 2. Needle.- 3. Biopsy Instrument.- 4. Catheter.- 5. Electrodes for Permanent Implantation.- 6. Archimedes Screw for Hematoma Evacuation.- 7. Endoscope.- 8. Laser.- F. Spinal Stereotactic Surgery.- 3: Expanding Field of Stereotactic Surgery.- I. Functional Stereotactics.- A. Movement Disorders.- 1. Parkinsonian Tremor.- 2. Essential Tremor.- 3. Cerebellar Dyskinesia.- 4. Torticollis Spastica.- B. Pain Syndromes.- 1. Stereotactic Lesions to Alleviate Pain.- 2. Stereotactic Stimulation with Electrodes to Achieve Pain Relief.- C. Intractable Epilepsy.- D. Psychiatric Disabling Disease.- E. Spasticity.- F. Spinal Stereotactic Procedures.- II. Mass Lesions Stereotactics.- A. Diagnostic Mass Lesions Stereotactics.- B. Therapeutic Mass Lesions Stereotactics.- 1. Aspiration and Evacuation of Fluids.- 2. Interstitial Radioisotope Application.- 3. Stereotactic Radiosurgery.- 4. Coagulation/Resection with Stereotactic Instruments.- 5. Intraneoplastic Drug Delivery with Stereotactic Instruments.- III. Localizing Stereotactics and Open Surgery.- A. Interventional Stereotactics.- B. Localizing Stereotactics.- 4: Modern Instrumentation.- I. Introduction.- II. CT Guided Stereotactic Apparatus; Technical Aspects.- A. Riechert-Mundinger System.- B. Leksell System.- C. Brown-Roberts-Wells System.- D. Other Computed Tomography Based Systems.- 1. CT Based Intracranial Landmark Technique of Gildenberg.- 2. Computerized, CT Guided, Stereotactic System with 3-D Reconstruction of Shelden and Jacques.- 3. Computer Monitored, CT Based, Stereotactic System with 3-D Reconstruction of Kelly and Alker.- III. CT Guided Stereotactic Surgery.- A. General Principles.- B. Advantages over Conventional Stereotactic Surgery.- C. Pitfall.- 5: Indications for Stereotactic Interventions.- I. Indications for Functional Stereotactic Interventions.- A. Movement Disorders.- 1. Parkinsonian Tremor.- 2. Essential Tremor.- 3. Cerebellar Tremor.- 4. Posttraumatic Movement Disorders.- 5. Torsion Dystonia.- 6. Torticollis Spastica.- 7. Hemi-Dystonia.- B. Intractable Pain.- 1. Cancer Pain.- 2. Chronic Intractable Pain.- C. Otherwise Intractable Epilepsy.- D. Psychiatric Disease.- II. Indications for Diagnostic Stereotactic Interventions.- A. Patients Without Previous History of Tumor Who Present a Single Mass Lesion.- B. Patients Without Previous History of Tumor Who Present Multiple Mass Lesions.- C. Patients with a Known Primary Tumor Elsewhere, Who Present a Single Mass Lesion, but Having no Signs of Metastasis Elsewhere in the Body.- D. Patients with a Known Primary Tumor Elsewhere, Who Present Multiple Mass Lesions in the Brain Without Other Metastatic Spread.- III. Indications for Therapeutic Stereotactic Interventions.- A. Evacuation of Fluids.- 1. Cystic Craniopharyngioma.- 2. Cystic Glioma.- 3. Subependymal or Leptomeningeal Cysts.- 4. Colloid Cyst of Third Ventricle.- 5. Brain Abscess.- 6. Primary Hematoma.- B. Interstitial Radioisotope Application.- C. Stereotactic Radiosurgery.- IV. Indications for Localizing Stereotactic Interventions.- A. Small Tumors in the White Matter.- B. Small Subcortical Arteriovenous Malformations.- C. Small White Matter Abscesses.- D. Lobar and Putaminal Hematomas.- E. Subcortical Foreign Bodies.- 6: Contraindications for Stereotactic Interventions.- I. Contraindications for Functional Stereotactic Interventions.- A. Movement Disorders.- B. Chronic Pain Syndromes.- C. Medically Refractory Epilepsy.- D. Psychiatric Disabling Disease.- E. Spasticity.- II. Contraindications for Diagnostic Stereotactic Interventions.- A. Resectable Lesions.- B. Normal Brain Tissue.- C. Intraventricular Tumors.- D. Lower Brainstem Lesions.- E. Vascular Lesions.- F. In or Near the Subarachnoid Space.- III. Contraindications for Therapeutic Stereotactic Interventions.- A. Aspiration and Evacuation of Fluids.- 1. Cystic Craniopharyngioma.- 2. Posttraumatic Hematoma.- B. Interstitial Irradiation of Tumors.- C. Stereotactic Radiosurgery.- IV. Contraindications for Localizing and Interventional Stereotactics.- A. Aneurysms.- B. Deep Seated Arteriovenous Malformations.- C. Foreign Bodies.- 7: Stereotactic Techniques.- I. Leksell's Apparatus.- II. Preparation of the Patient.- A. Diagnostic and Therapeutic Stereotactics.- B. Functional Stereotactics.- C. Localizing Stereotactics.- III. The Positioning of the Patient.- 8: Pitfalls.- I. Technical Problems.- A. The Superficial Target.- B. Clinical Signs of Increased ICP.- C. Bleeding at the Target Site.- II. Pitfalls by Underlying Pathology.- A. Vascular Lesions.- B. False Positive and False Negative Results.- C. Unsuspected Mass Lesions.- 9: Functional Stereotactics.- I. Extrapyramidal and Cerebellar Tremor.- A. Stereotactic Thalamotomy Prior to L-dopa Institution.- B. Stereotactic Thalamotomy After L-dopa Institution.- II. Intractable Pain Syndromes.- III. Brainstem Stereotactic Surgery in Cancer Pain.- 10: Mass Lesions Stereotactics.- I. Discussion of Deep Seated Tumors According to Growth Pattern.- A. Diffusely Growing Tumors.- B. Butterfly Tumors.- C. Multiple Tumors.- D. Small Deep Seated Tumors.- E. Cystic Tumors.- F. Brainstem Tumors.- G. Pineal Gland Tumors.- H. Skull Base Invading Tumors.- II. Presentation of Our Own Material and Discussion of Other Reports.- 11: Stereotactic Localization with Subsequent Lesion Treatment.- I. Introduction.- II. Colloid Cysts of the Third Ventricle.- III. Primary Deep Seated Hematomas.- A. Hypertensive Intracerebral Hematomas.- B. Primary Brainstem Hematomas.- IV. Deep Seated Small Arteriovenous Malformations.- A. Introduction.- B. Stereotactic Aiming and Open Surgery in Stereotactic Space in Small and Deep Seated AVM's.- V. Stereotactic Aiming and Open Surgery in Stereotactic Space for Small and Deep Seated Tumors.- 12: Illustrative Cases.- 13: Integration of Stereotactics in Clinical Neurosurgery.- I. Introduction.- II. The Computer in Neurosurgery.- A. The Computer and Functional Stereotactics.- B. The Computer and Diagnostic and Therapeutic Stereotactics.- C. The Computer and Localizing Stereotactics.- 14: Future Possibilities.- I. Introduction of Magnetic Resonance Imaging.- II. Future Applications of Stereotactics in Functional Disorders.- III. Future Applications of Stereotactics in Mass Lesions.- IV. Conclusion.- References.