We give a description of stereotaxic methodology as originally elaborated by the S.te Anne Hospital School in Paris, and successively modified and utilised in Niguarda Hospital in Milan. Performing a stereotactic arteriography and ventriculography should allow the appreciation of minimal modification of vascular anatomy, identification of sulci and gyri by utilising stereoscopic technique and the proportional grid, based on bicommissural line, evaluation of the morphological abnormalities and their precise reconstruction in the intracranial space. Anatomical information obtained by this kind of examinations are essential for intracerebral stereo-EEG investigation and for planning surgical procedure.