The E-meter is a device for displaying and/or recording the electrodermal activity (EDA) of a human being. The device is used frequently for auditing in Scientology and divergent groups, but devices similar to the Scientology E-meter have been used for more than a century by counselors of psychology and psychoanalysis. Such devices have been used as a research tool in many human studies, and as one component of the Keeler polygraph (lie detector) system. The efficacy and legitimacy of Scientology's use of the E-meter has been subject to extensive debate and litigation and in accordance with a federal court order, the Church of Scientology now publishes disclaimers in its books and publications declaring that the E-meter "by itself does nothing" and that it is used specifically for spiritual purposes.

The E-meter is a device for displaying and/or recording the electrodermal activity (EDA) of a human being. The device is used frequently for auditing in Scientology and divergent groups, but devices similar to the Scientology E-meter have been used for more than a century by counselors of psychology and psychoanalysis. Such devices have been used as a research tool in many human studies, and as one component of the Keeler polygraph (lie detector) system. The efficacy and legitimacy of Scientology's use of the E-meter has been subject to extensive debate and litigation and in accordance with a federal court order, the Church of Scientology now publishes disclaimers in its books and publications declaring that the E-meter "by itself does nothing" and that it is used specifically for spiritual purposes.