After it is clear that one has epilepsy, if surgical treatment is being considered, it is critical to establish where in the brain the epileptogenic focus is located. The preoperative evaluation of epilepsy is to find where in the brain the epileptic focus is located so that the surgical plan can be determined. The current national and international consensus is that it is appropriate to utilize a comprehensive examination rather than a single method as a substitute. Any minute information about the patient is informative in locating the epileptic focus, such as the patient’s developmental history at birth, the presence of febrile convulsions, history of trauma, history of unexplained hyperthermia, familial genetic history, and surgical history. The patient’s seizure trigger, seizure aura, and seizure type (performance during seizure) are particularly important for the localization of the epileptic focus. Physical examination of the patient: e.g. visual field, whether it is left- or right-handed, limb movement (muscle strength and tone). MRI of the head, applying a special sequence of scans specific to patients with epilepsy, can detect microscopic lesions associated with epilepsy. And functional magnetic resonance (fMRI) can determine the relationship between functional areas and epileptic foci to determine surgical options. Video EEG (VEEG): Long-range video EEG monitoring, especially seizure EEG, combined with the type of seizure seen on video, can determine whether the patient has focal epilepsy or total epilepsy. In the case of focal epilepsy, it is even possible to determine the specific site, whether it is the left or right hemisphere, whether it is that lobe on one side, or whether it is specific to a particular brain gyrus. Intracranial electrode cortical EEG: The electrodes are placed directly on the surface of the cerebral cortex, reducing interference from the scalp, skull, and meninges. It is currently the gold standard for low ang for epileptic foci and for localizing functional brain areas.