Electrodennal activity refers to electrical changes across the skin in areas of the body that are psychologically responsive. The eccrine sweat glands are the primary detenninant of electrodennal activity, and these are psychologically active especially on the palms of the hands and the soles of the feet. As a matter of convenience, electrodennal activity is most often recorded from the palms. Over the years, the electrodennal response has been known as the psychogalvanic reflex, the galvanic skin response, the skin resistance response, the skin conductance response, and the skin potential response. The tenns psychogalvanic reflex and galvanic skin response have fallen into disuse among scientists, but are still to be found in psychology text books. of its early discovery, ease of measurement, and often easily observable Because response to experimental manipulations, the recording of electrodennal activity is one of the most frequently used methods in psychophysiology. Indeed, in the early years following the founding of the Society for Psychophysiological Research, electrodennal research so dominated the field that people worried that the society was simply an electrodennal society. Although other psychophysiological techniques have emerged as equally strong contributors to psychophysiology, electrodennal research continues to be important throughout the world. As a result of this massive research investment, there has been great progress in understanding electrodennal phenomena, as well as major advances in recording methods since the phenomenon was discovered.