thumb|300px|A demonstration of Scientology auditing showing position of participants and tools
Auditing, also called processing, is a central practice in Scientology in which a trained "auditor" asks structured questions intended to help a participant identify and address past experiences and emotional difficulties. Most auditing uses an E-meter, a device the Church of Scientology describes as a spiritual tool for detecting areas of mental or spiritual trauma, though courts and scientists have found it to have no medical or scientific validity. Auditing is presented as the primary method for advancing up Scientology's Bridge to Total Freedom, a graded series of levels involving procedures and rundowns, using concepts such as the reactive mind, engrams, and past‑life incidents and implants. Scholars and critics have variously described auditing as a form of psychological conditioning, hypnosis, or pseudotherapy, and have raised concerns about its methods, the misuse of confidential session records, and its space‑opera cosmology. There have been legal, regulatory, and ethical controversies related to its unproven medical claims, misuse of private information, the use of child labor, and the death of some participants.<!--Note: This lead paragraph is ed into the Scientology article.-->
Terminology
L. Ron Hubbard assigned special meanings to many ordinary English words when he wrote about Scientology, and Scientologese has become a language in itself. These are some very basic meanings of words Scientology uses when describing this subject.
: The procedures where two individuals work together to improve one of the person's abilities and to reduce or eliminate their neuroses.
: A trained Scientologist who is helping another individual through the use of auditing techniques. An auditor is only allowed to audit processes (on others) up to the level of training they have completed (their 'class').