This chapter provides an overview of the history of electrophysiological research, beginning with Luigi Galvani’s discovery, with a particular emphasis on the application of electrophysiological techniques in glial cell studies. We explore the electrophysiological properties of glial membranes, focusing specifically on astrocytes, which are distinguished among glial cells for their unique electrical activity, as studied so far using intracellular recording techniques. Furthermore, the chapter addresses the technical challenges of extracellular measurements in glial cells, due to their small and slow electrical activity. Tools designed to improve electrode performance for these measurements are introduced, along with key studies on extracellular electrophysiology in glial cells conducted to date.