As in all fields of surgery, the current trend in neurosurgery is towards less-invasive procedures and the shorter hospital stays that result from them. Therefore, stereotactic techniques are an indispensable tool for the modern neurosurgeon and have been dramatically improved by the recent revolution in digital image guidance technology. These techniques provide a relatively straightforward, accurate, and safe method to approach intracranial targets that are defined by either anatomical or functional characteristics. Anatomically defined targets include brain tumors and abscesses, as well as other structural lesions. Targeting for anatomical disorders relies entirely on patient-specific anatomy derived from radiographs (e.g., ventriculography, rarely used today) or tomograms (e.g., CT, MRI) for localization. In addition, functional imaging modalities (e.g., fMRI), metabolic imaging modalities (e.g., positron emission tomography (PET)), and MR spectroscopy can be utilized in conjunction with other imaging modalities to help with target planning and visualization. Functionally defined structures include the various nuclei of the basal ganglia and thalamus that are targeted for pain and movement disorders (e.g., Parkinson's disease, essential tremor, and dystonia), as well as other conditions such as obsessive-compulsive disorder. Targeting for functional disorders typically combines computerized imaging with intraoperative electrophysiological mapping for localization, although anatomical techniques can be used alone as well.