Motor evoked potentials (MEPs) have steadily expanded in their scope and complexity of use in the field of intraoperative neurophysiology over the past century and even more so over the past few decades. Much has been learned about this technique since its earliest application to the exposed cortex. Electrical techniques to overcome the inhibitory effects of general anesthetics and penetrate the resistive barrier of the skull have allowed for the development of a wide range of methods to protect the voluntary motor pathway of patients during a wide range of surgical procedures, ranging from resection of supratentorial brain lesions to microsurgical and endovascular treatment of neurovascular pathologies to lateral approaches for lumbar spinal procedures. An intimate understanding of the anatomy and physiology of the motor pathway, as well as a mastery of electrical stimulation principles, is requisite for successful monitoring of the motor pathway by means of cortically evoked motor evoked potentials.