Dianetics is a set of ideas and practices regarding the metaphysical relationship between the mind and body which was created by L. Ron Hubbard and is practiced by followers of Scientology. Hubbard coined Dianetics from the Greek stems dia, meaning through, and nous, meaning mind.

Dianetics divides the mind into three parts: the conscious "analytical mind," the subconscious "reactive mind", and the somatic mind. The goal of Dianetics is to remove the "reactive mind", which Scientologists believe prevents people from becoming more ethical, more aware, happier and saner. The Dianetics procedure to achieve this is called "auditing". Auditing is a process whereby a series of questions are asked by the Scientology auditor, in an attempt to rid the auditee of the painful experiences of the past which scientologists believe to be the cause of the "reactive mind."

When Hubbard formulated Dianetics, he described it as "a mix of Western technology and Oriental philosophy". He said that Dianetics "forms a bridge between" cybernetics and General Semantics (a set of ideas about education originated by Alfred Korzybski, which received much attention in the science fiction world in the 1940s) — a claim denied by scholars of General Semantics, including S. I. Hayakawa, who expressed strong criticism of Dianetics as early as 1951. Hubbard claimed that Dianetics could increase intelligence, eliminate unwanted emotions and alleviate a wide range of illnesses he believed to be psychosomatic. Among the conditions purportedly treated were arthritis, allergies, asthma, some coronary difficulties, eye trouble, ulcers, migraine headaches, 'sexual deviation' (a category which for Hubbard included homosexuality) and even death. Hubbard variously defined Dianetics as "a spiritual healing technology" and "an organized science of thought."

Dianetics predates Hubbard's classification of Scientology as "applied religious philosophy". Early in 1951, he expanded his writings to include teachings related to the soul, or "thetan". Dianetics is also practiced by independent groups, collectively called the Free Zone. The Church of Scientology disapproves of Free Zone activities and has prosecuted them in court for misappropriation of Scientology and Dianetics copyrights and trademarks.

Dianetics has achieved no acceptance as a scientific theory and scientists cite Dianetics as an example of a pseudoscience (see below).

Read more about Dianetics:  History, Basic Concepts, Scientific Evaluation and Criticisms, Procedure in Practice, Autocontrol