Hubbard, theretofore best known as a science fiction author, first mentioned Dianetics in a series of articles in Astounding Science Fiction magazine during the 1940s. Dianetics appeared as a complete system of published self-improvement techniques in the book Dianetics: The Modern Science of Mental Health (DMSMH) on May 9, 1950. There followed the more organized Science of Survival in 1951, and finally Dianetics 55! in 1955, by which time Hubbard had characterized Dianetics as a minor sub-study of Scientology.
DMSMH quickly became a best-seller, and spawned a multitude of (mostly short-lived) "Dianetics clubs" and similar organizations. The novelty of Dianetics soon wore off, and Hubbard started to encounter public criticism as well as legal action from the established mental health community, whom he had taken every opportunity to attack and insult in his book.
In 1952, Hubbard presented Scientology, a religious philosophy based on the same basic principles as his Dianetic techniques, and claimed the protection afforded to all religions by the United States Constitution. Dianetics: The Evolution of a Science (1983) gives Hubbard's (possibly ghostwritten) account of his development of dianetics and its eventual evolution into Scientology. By the time he died in 1986, Hubbard had published hundreds of books on Scientology, and only a few on Dianetics.
Dianetics presents itself as a systemic method of identifying the causes of and relieving many of an individual's mental, emotional or (psychosomatically) physical problems. Fundamental to the system is the concept of the engram, which is defined as "a definite and permanent trace left by a stimulus on the protoplasm of a tissue.". Engrams appear during periods of psychological distress or trauma, and lie at the root of all mental disorders.
Some regard Dianetics as a pseudoscience, as it presents itself as a "scientific" system of knowledge, yet fails to meet the requirements of the scientific method. Many people also view dianetics as pure science fiction and a practical joke, based upon testimony by witnesses that Hubbard stated he would create a science-fiction religion to make money.
Hubbard in Dianetics states: "[Dianetics is]...an organized science of thought built on definite axioms: statements of natural laws on the order of those of the physical sciences". Critics would argue that the phrase 'definite axiom' expressess an oxymoron, and regardless, a science cannot depend on axioms, only on hypotheses based on experimental evidence.
Dianetics provided the seed from which the philosophical framework of Scientology grew. This relationship is also suggested by the cover image of a volcano on the Dianetics books, relating to the Xenu event (see Scientology beliefs and practices). On this basis Scientologists often jokingly refer to the book Dianetics: The Modern Science of Mental Health as The Old Testament.
Most Scientologists today regard the original Dianetics techniques as valid but outdated, and view Dianetics largely as an easy introduction to Scientology. As of 2001, the Church of Scientology continued to run television advertisementss promoting Dianetics: The Modern Science of Mental Health. According to the Los Angeles Times, and managers of Walden Books, B. Dalton Bookstore, other bookstore managers and former Scientology leaderss, the Church asked its members to purchase large quantities of DTMSOMH with their own money, or with money supplied by the Church, for the sole purpose of keeping the book on the New York Times bestseller list.