Publisher Summary This chapter focuses on the development of neurosurgical approaches in the treatment of epilepsy, which begins with the impact of electroencephalography (EEG) and the emergence of temporal lobe surgery. EEG is the most important advance in the development of modern surgical treatment for epilepsy as a laboratory tool for diagnosing epileptic disorders and localizing focal epileptogenic abnormalities. Furthermore, neurocognitive testing is an important part of modern presurgical evaluation. The discipline of neuropsychology has benefited enormously from studies of patients with focal epilepsy in an epilepsy surgery setting, both before and after surgical resection. X-ray computed tomography (CT) was the first computerized tomographic approach to visualizing the entire brain in three dimensions. The development of magnetic resonance imaging (MRI) greatly improved resolution of discrete structural lesions that might be epileptogenic, particularly disorders of cortical malformation, such as focal cortical dysplasia, making lesion-directed surgery increasingly possible in patients who, in the past, would have been diagnosed as having cryptogenic focal epilepsy and considered to be poor surgical candidates.