Followers of the Scientology movement maintain a wide variety of beliefs and practices. The core belief holds that a human is an immortal, spiritual being (thetan) that is resident in a physical body. The thetan has had innumerable past lives, some of which, preceding the thetan's arrival on Earth, were lived in extraterrestrial cultures. Based on case studies at advanced levels, it is predicted that any Scientologist undergoing auditing will eventually come across and recount a common series of past-life events.

Scientology describes itself as the study and handling of the spirit in relationship to itself, others, and all of life. Scientologists also believe that people have innate, yet suppressed, power and ability, which can be regained if cleared of unwanted behavioral patterns and discomforts. Believers reach their full potential "when they understand themselves in their true relationship to the physical universe and the Supreme Being." There have been many scholarly studies of Scientology, and the books are freely available in bookshops, churches, and most libraries.

The Church of Scientology believes that "Man is basically good, that he is seeking to survive, (and) that his survival depends on himself and his attainment of brotherhood with the universe", as stated in the Creed of the Church of Scientology.

Hubbard taught that there were three "Parts of Man", the spirit, mind, and body. The first of these is a person's "true" inner self, a "theta being" or "thetan". While the thetan is akin to the idea of the soul or spirit found in other traditions, Hubbard avoided terms like "soul" or "spirit" because of their cultural baggage. Hubbard stated that "the thetan is the person. You are YOU in a body." According to Hubbard, the thetan uses the mind as a means of controlling the body. Scientology teaches that the thetan usually resides within the human skull but can also leave the body, either remaining in close contact with it or being separated altogether.

According to Scientology, a person's thetan has existed for trillions of years, having lived countless lifetimes, long before entering a physical body it may now inhabit. In their original form, the thetans were simply energy, separate from the physical universe. Each thetan had its own "Home Universe", and it was through the collision of these that the physical MEST universe emerged. Once MEST was created, Scientology teaches, the thetans began experimenting with human form, ultimately losing knowledge of their origins and becoming trapped in physical bodies. Scientology also maintains that a series of "universal incidents" have undermined the thetans' ability to recall their origins.

Hubbard taught that thetans brought the material universe into being largely for their own pleasure. The universe has no independent reality but derives its apparent reality from the fact that thetans agree it exists. Thetans fell from grace when they began to identify with their creation rather than their original state of spiritual purity. Eventually they lost their memory of their true nature, along with the associated spiritual and creative powers. As a result, thetans came to think of themselves as nothing but embodied beings.

According to L. Ron Hubbard's 1952 book A History of Man, published in 1952, there are two entities housed by the human body: a genetic entity (whose purpose is to carry on the evolutionary line) and a "Thetan" or consciousness "that has the capacity to separate from body and mind." According to Hubbard, "In man's long evolutionary development the Thetan has been trapped by the engrams formed at various stages of embodiment." Scientology training is aimed at clearing the person of all engrams, thus creating an "Operating Thetan". "Among the abilities of the Operating Thetan is the soul's capacity to leave and operate apart from the body."

People are viewed as spiritual beings that have minds and bodies, and a person's "spiritual essence" is called the "Thetan". Scientology teaches that "a thetan is the person himself, not his body or his name or the physical universe, his mind or anything else." According to the doctrine, "one does not have a thetan, he is a thetan."

Hubbard referred to the physical universe as the MEST universe, meaning "Matter, Energy, Space and Time". In Scientology's teaching, this MEST universe is separate from the theta universe, which consists of life, spirituality, and thought. Scientology teaches that the MEST universe is fabricated through the agreement of all thetans (souls or spirits) that it exists, and is therefore an illusion that is only given reality through the actions of thetans themselves.

In Scientology, "exteriorization" refers to the thetan leaving the physical body, if only for a short time, during which it is not encumbered by the physical universe and exists in its original state. Scientology aims to "exteriorize" the thetan from the body so that the thetan remains close to the body and capable of controlling its actions, but not inside of it, where it can confuse "beingness with mass" and the body. In this way, it seeks to ensure the thetan is unaffected by the trauma of the physical universe while still retaining full control of the mind and body. Some Scientologists claim that they experienced exteriorization while auditing.

One of Scientology's goals is to free the thetan from the confines of the physical MEST universe, thus returning it to its original state. This idea of liberating the spiritual self from the physical universe has drawn comparisons with Buddhism. Although Hubbard's understanding of Buddhism during the 1950s was limited, Scientological literature has presented its teachings as the continuation and fulfillment of The Buddha's ideas. In one publication, Hubbard claimed to be both Maitreya, the future enlightened being prophesied in some forms of Mahayana Buddhism, and the Antichrist. Some Scientologists regard Hubbard as Maitreya. The concept of the thetan has also been observed as being very similar to those promulgated in various mid-20th century UFO religions.

According to Lawrence Wright, author of Going Clear, exteriorization "is the sense that one has actually left his physical being behind".

Scientology teaches the existence of reincarnation; Hubbard taught that each individual has experienced "past lives", although generally avoided using the term "reincarnation" itself. The movement claims that once a body dies, the thetan enters another body which is preparing to be born. It rejects the idea that the thetan will be born into a non-human animal on Earth. In Have You Lived Before This Life?, Hubbard recounted accounts of past lives stretching back 55 billion years, often on other planets.

At death, the spirit will leave the body: "Life and personality go on. The physical part of the organism ceases to function." Scientology believes in the "immortality of each individual's spirit," therefore making death not a significant worry. The spirit acquires another body necessary for growth and survival. The primary goal is to achieve an individual's true identity.

According to Scientology doctrine, salvation is achieved through "clearing" engrams and implants, the source of human misery, through the auditing process. Salvation is limited to the current life and there is no "final salvation or damnation", author Richard Holloway writes. "Life is not a one-shot deal. There is only the eternal return of life after life." According to Scientology beliefs, "the individual comes back. He has a responsibility for what goes on today since he will experience it tomorrow."

According to Scientology beliefs, Scientology itself is a blend of science and spirituality, with a belief in an immortal spirit and in improving that spirit here on Earth using Scientology's methods. Scientologists do not typically dwell on Heaven or Hell or the afterlife, instead focusing on the spirit. Many Scientologists also belong to other churches.

In the Scientology book, A History of Man, Hubbard discusses that a human's past experiences make up that person's present identity. These include experiences such as atoms, seaweed, plankton, and clams, pointing to the belief in recurring lives.

Scientology emphasizes the importance of "survival", subdividing into eight classifications called "the eight dynamics". The optimum solution to any problem is the one that brings the greatest benefit to the greatest number of dynamics. The eight dynamics are:

1. The first dynamic is the urge toward survival of self.
2. The second dynamic is the urge toward survival through sex or procreation. There are two subdivisions: (a) the sexual act itself and (b) the family unit, including the rearing of children.
3. The third dynamic is the urge toward survival through groups, for example a school, a club, a team, a town, a nation.
4. The fourth dynamic is the urge toward survival through all mankind.
5. The fifth dynamic is the urge toward survival through life forms such as animals, birds, insects, fish, and vegetation.
6. The sixth dynamic is the urge toward survival as the physical universe, which is called MEST (for matter, energy, space, time).
7. The seventh dynamic is the urge toward survival through spirits or as a spirit. Anything spiritual would come under the seventh dynamic.
8. The eighth dynamic is the urge toward survival through the Supreme Being or infinity.

Hubbard introduced the Scientology cross in the mid-1950s as a religious symbol for Scientology. The eight points of the cross symbolize the eight dynamics.

The Church of Scientology states that it has no set dogma on God and allows individuals to come to their own understanding of God. In Scientology, "vastly more emphasis is given to the godlike nature of the [individual] and to the workings of the human mind than to the nature of God." Hubbard did not clearly define God in Scientology. When pressed about their belief, Scientologists mention the "eighth dynamic" which they say is the "God dynamic".

Scientologists affirm the existence of a deity without defining or describing its nature. L. Ron Hubbard wrote in his book Science of Survival, "No culture in the history of the world, save the thoroughly depraved and expiring ones, has failed to affirm the existence of a Supreme Being. It is an empirical observation that men without a strong and lasting faith in a Supreme Being are less capable, less ethical and less valuable." Instead of defining God, members assert that reaching higher states of enlightenment will enable individuals to make their own conclusions about the Supreme Being.

The tone scale is a key construct throughout Scientology and is used to gauge someone's value in society or determine how best to control or communicate with someone. Hubbard introduced the tone scale with his 1951 book Science of Survival and expanded it since then. The concept is a vertical scale of points from −40.0 to +40.0, each representing an emotion or other mental concept. The midpoint is 0.0, labelled "body death". From 0.0 upward is the emotional tone scale, where points such as apathy, grief, fear, anger, boredom, contentment, cheerfulness, enthusiasm, and serenity of beingness at the top are labeled. Points below 0.0 are mental concepts rather than emotions, such as shame, blame, regret, sacrifice, hiding, and total failure. In common Scientology parlance, a person high on the tone scale is called uptone or high toned, and one low on the tone scale is called downtone or low toned.

According to Hubbard, one's tone affects a person's attitude, their ability to relate with others, and even body odors. The higher on the scale, the more emotionally alive someone would be. Lower tones, Hubbard asserted, should be exiled from society. During the auditing process, the auditor is trained to observe the client's emotional state using the tone scale, to raise an individual on the tone scale and improve his abilities.

The Scientology symbol is made up of two triangles with an "S" connecting them. The top triangle is called the KRC triangle, symbolizing the related concepts of knowledge, responsibility, and control. The lower triangle is called the ARC triangle, symbolizing the related concepts of affinity, reality, and communication, and all three together represent understanding. The large connecting "S" stands for "Scientology".

Scientology teaches that improving one of the three aspects of the KRC or ARC triangle will increase the other two. In the ARC triangle, communication is held to be the most important.

Among Scientologists, the letters ARC are used as an affectionate greeting in personal communication, for example, at the end of a letter. Social problems are ascribed to breakdowns in ARC – in other words, a lack of agreement on reality, a failure to communicate effectively, or a failure to develop affinity. These can take the form of overts – harmful acts against another, either intentionally or by omission – which are usually followed by withholds – efforts to conceal the wrongdoing, which further increase the level of tension in the relationship.

Scientology teaches that progress on The Bridge to Total Freedom requires and enables attaining high moral and ethical standards. According to Hubbard, the goal of ethics is to remove impediments to survival, and ethics is essentially a tool to "get technology in", meaning Scientology's use of the term technology. Stephen A. Kent describes Scientology ethics as "a peculiar brand of morality that uniquely benefitted [the Church of Scientology] [...] In plain English, the purpose of Scientology ethics is to eliminate opponents, then eliminate people's interests in things other than Scientology. In this 'ethical' environment, Scientology would be able to impose its courses, philosophy, and 'justice system' – its so-called technology – onto society."

Gender and sexuality have been controversial issues in Scientology's history. Women may become ministers and rise through the church ranks in the same manner as men. Hubbard's writing makes androcentric assumptions through its use of language. Critics of Scientology say that Hubbard was a misogynist. Hubbard's use of language was also heteronormative. He described same-sex attraction as a perversion and physical illness, rendering homosexuals "extremely dangerous to society". Various Free Zone Scientologists have alleged that they encountered homophobia within the church. The church's stance on same-sex sexuality has drawn criticism from gay rights activists.

The church considers itself scientific, although this belief has no basis in institutional science. According to religious scholar Mikael Rothstein Scientologists believe that "all religious claims can be verified through experimentation". Scientologists believe that their religion was derived through scientific methods, that Hubbard found knowledge through studying and thinking, not through revelation. The "science" of Dianetics, however, was never accepted by the scientific community. Rothstein also writes that there is a possibility that Scientology partly owes its existence to the conflict with the conventional scientific community, which hindered Hubbard's original intention. Religious scholar Dorthe Refslund Christensen notes that Scientology differs from the scientific method in that Scientology has become increasingly self-referential, while true science normally compares competing theories and observed facts.

Hubbard initially claimed and insisted that Dianetics was based on the scientific method. He taught that "the scientific sensibilities [carry] over into the spiritual realities one encounters via auditing on the e-meter." Scientologists commonly prefer to describe Hubbard's teachings with words such as knowledge, technology, and workability rather than belief or faith. Hubbard described Dianetics and Scientology as "technologies" based on his claim of their "scientific precision and workability." Hubbard attempted to "break down the barrier between scientific (objective, external) and religious (subjective, internal) forms of knowledge." Hubbard describes Scientology's epistemology as "radically subjective: Nothing in Scientology is true for you unless you have observed it and it is true according to your observation." This is a type of self-legitimation through science which is also found in other religions such as Christian Science, Religious Science, and Moorish Science Temple of America.

Sociologist William Sims Bainbridge cites Scientology's origins in the subcultures of science fiction and "harmony" with scientific cosmology. Science fiction, viewed to work for and against the purposes of science, has contributed to the birth of new religions, including Scientology. While it promotes science, it distorts it as well. Science fiction writer A.E. van Vogt based the early development of Dianetics and Scientology on a novel based on General Semantics, a self-improvement and therapy program created by Alfred Korzybski to cure personal and social issues.

Scientologists believe that Hubbard "discovered the existential truths that form their doctrine through research," thus leading to the idea that Scientology is science. Hubbard created what the church would call a "spiritual technology" to advance the goals of Scientology. According to the church, "Scientology works 100 percent of the time when it is properly applied to a person who sincerely desires to improve his life." The underlying claims are that Scientology is "exact" and "certain". Michael Shermer, writing for Scientific American in 2011, said that Scientology's methods lacked enough study to qualify as a science, but that the story of Xenu and Scientology's other creation myths were no less tenable than other religions.

B. Hubbard, J. Hatfield, and J. Santucci compare Scientology's view of humanity to the Yogachara school of Buddhism, saying that both have been described as "the most scientific" among new and traditional religions, respectively. They cite technical language and claims that teachings were developed through observation and experimentation. They also emphasize that many investigators and researchers consider Scientology to be a pseudoscience because of its absolute and meta-empirical goals.

Scholar Kocku von Stuckrad stated that Scientology is an example of the phenomenon of both the "scientification of religion" and the "sacralization" of science. Donald A. Westbrook argues that there is an "ongoing and dialectical relationship" between religion and science in Hubbard's teachings.

The psychiatric establishment rejected Hubbard's theories in the early 1950s. Since then, Hubbard was vehemently opposed to psychiatry and psychology. Scientologists view psychiatry as a barbaric and corrupt profession and consider mental illness a fraud. They allege that psychiatrists were responsible for the Holocaust, apartheid and 9/11.

Scientology established the anti-psychiatry lobby group Citizens Commission on Human Rights (CCHR) which operates an exhibit Psychiatry: An Industry of Death. CCHR has helped legislators draft bills, though bills in Florida and Utah failed which would have made it a crime for school teachers to suggest to parents that their child might be suffering from a mental health condition.

The church makes it clear that Hubbard is considered the sole source of Dianetics and Scientology: "The Scientology religion is based exclusively upon L. Ron Hubbard's research, writings and recorded lectures – all of which constitute the Scriptures of the religion." His work, recorded in 500,000 pages of writings, 6,500 reels of tape and 42 films, is archived for posterity. The Religious Technology Center holds "the ultimate ecclesiastical authority and the pure application of L. Ron Hubbard's religious technologies."

Individuals applying Hubbard's techniques who are not officially connected to the Church of Scientology are considered part of the "Free Zone". Some of these individuals were litigated against for using and modifying the practices for their own use and that of others, thereby infringing the law on patent, trademarks, or trade secrets.

The Church of Scientology requires that all members sign a legal waiver which covers their relationship with the Church of Scientology before engaging in Scientology services.

The central practice of Scientology is an activity known as auditing, which seeks to elevate an adherent to a state of Clear, one of freedom from the influences of the reactive mind. The practice is one wherein a counselor called an "auditor" addresses a series of questions to a preclear, observes and records the preclear's responses, and acknowledges them. An essential element in all forms of auditing is not to suggest answers to the preclear or invalidate or degrade what the preclear says in response. It is of utmost importance that the auditor create a safe and distraction-free session environment.

The term clear derives from a calculator button that deletes previous calculations. According to Scientology beliefs, Clears are "optimal individuals", and "they have been cleared of false information and memories of traumatic experiences that prevent them from adapting to the world around them in a natural and appropriate fashion." Scientologists believe that clears become more successful in their daily lives and are "healthier, experience less stress, and possess better communication skills than non-Scientologists."

"Auditing" is sometimes considered controversial, because auditing sessions are permanently recorded and stored within "preclear folders". Scientologists believe that the practice of auditing helps them overcome the debilitating effects of traumatic experiences, most of which have accumulated over a multitude of lifetimes. The folders are kept in accordance with the Priest/Penitent legal parameters which do not allow these folders to be seen or used for any other purpose or seen by any others who are not directly involved in supervising that person's auditing progress.

Auditors are required to become proficient with the use of their E-meters. The device measures the subject's galvanic skin response like a polygraph (lie detector), but with only one electrode per hand rather than multiple sensors. The E-meter is primarily used in auditing, which "aims to remove (engrams) to produce a state of 'clear.'" Auditors do not receive final certification until they have completed an internship, and have demonstrated a proven ability in the skills they have been trained in. Auditors often practice their auditing with each other, as well as friends or family. Church members sometimes pair up during training, doing the same course simultaneously so that they can audit each other up through the various Scientology levels.

According to scholar Harriet Whitehead, the Church of Scientology "has developed a fine-tooled hierarchically organized system of audit (training) sessions where the technology of these sessions, in fact, is the treatment leading to processes of renunciation and eventually reformulation in the individual," which is similar to psychoanalysis.

Among Scientology's basic tenets are the belief that human beings are immortal, that a person's life experience transcends a single lifetime, and that human beings possess infinite capabilities. Scientology presents two major divisions of the mind. The "reactive mind" is thought to absorb all pain and emotional trauma, while the "analytical mind" is a rational mechanism which is responsible for consciousness. The reactive mind stores mental images which are not readily available to the analytical (conscious) mind; these are referred to as "engrams". Engrams are painful and debilitating; as they accumulate, people move further away from their true identity. Avoiding this fate is Scientology's basic goal. Dianetic auditing is one way by which the Scientologist may progress toward the 'Clear' state, winning gradual freedom from the reactive mind's engrams, and acquiring certainty of their reality as a thetan. Hubbard's differentiation of the reactive mind and the analytical mind forms one of the basic tenets of Dianetics. The analytical mind is similar to the conscious mind, which processes daily information and events. The reactive mind produces the mind's "aberrations" such as "fear, inhibition, intense love and hate and various psychosomatic ills" which are recorded as "engrams".

Scientology believes people have hidden abilities that have not yet been fully realized. It is believed that increased spiritual awareness and physical benefits are accomplished through counseling sessions referred to as "auditing". Through auditing, it is said that people can solve their problems and free themselves of engrams. This restores them to their natural condition as thetans and enables them to be "at cause" in their daily lives, responding rationally and creatively to life events rather than reacting to them under the direction of stored engrams. Accordingly, those who study Scientology materials and receive auditing sessions advance from a status of "Preclear" to "Clear" and "Operating Thetan". Scientology's utopian aim is to "clear the planet", a world in which everyone has cleared themselves of their engrams.

Auditing is a one-on-one session with a Scientology counselor or "auditor". It bears a superficial similarity to confession or pastoral counseling, but the auditor records and stores all information received and does not dispense forgiveness or advice the way a pastor or priest might do. Instead, the auditor's task is to help people discover and understand engrams and their limiting effects for themselves. Most auditing requires an E-meter, a device that measures minute changes in electrical resistance through the body when a person holds electrodes (metal "cans"), and a small current is passed through them.

Scientology believes that watching for changes in the E-meter's display helps locate engrams. Once an area of concern has been identified, the auditor asks the individual specific questions about it to help them eliminate the engram and uses the E-meter to confirm that the engram's "charge" has been dissipated and the engram has been cleared. As the individual progresses, the focus of auditing moves from simple to increasingly complex engrams. At the more advanced OT auditing levels, Scientologists perform solo auditing sessions, acting as their own auditors.

Advocated by Scientology founder L. Ron Hubbard, silent birth describes "the process of childbirth where labor and delivery is done in a calm and loving environment." To provide quiet surroundings for the baby's delivery, individuals in their immediate vicinity are prompted not to speak. According to Scientology practices, silent birth is "mandatory to provide the best possible environment for the pregnant mother and her new baby." Shouting, laughing, or making loud remarks must be avoided while the baby is being pushed out. According to The Multimedia Encyclopedia of Women in Today's World, "its origins are fundamentally rooted in the principle that women, particularly expectant mothers, be given the utmost care and respect."

Scientologists also undergo training aside from auditing, which consists of several levels of courses about daily life improvement using various tools and auditing techniques so that members can perform the same procedure as other Scientologists.

Scientology discourages secondary interpretation of its writings. Scientologists are taught to consult only official sources, and never convey their own interpretation of concepts in their own words.

Hubbard described three barriers to study: lack of mass, too steep a gradient, and the misunderstood word. Scientology teaches that a student who learns only ideas, without also seeing the thing in real life that they are studying (the mass) or at least a picture of it, would suffer feeling dizzy or bored or angry—the remedy would be to provide the student with some mass of the thing they are studying. If a student does not know the fundamentals of a subject and advances too quickly to higher levels, they would feel confused—the remedy for too steep a gradient would be to drop back down to the earlier level the person thought they knew well but did not. When a student reads past a word they do not fully understand, they would "go blank", yawn, or seem distracted—the remedy would be to find the word they did not know and look it up in a dictionary, then continue studying.

In Scientology, "misinformation or miscommunication is analogous to original sin, inhibiting individual growth and relationships with others." The "misunderstood word" is a key concept in Scientology, and failure in reading comprehension is attributed to it. Scientology focuses heavily on dictionaries. The Church of Scientology includes glossaries in most books and even publishes several dictionaries covering Scientology-specific terminology, words, phrases, and abbreviations. Critics have accused Hubbard of "loading the language" and using Scientology jargon to keep Scientologists from interacting with others outside of Scientology.

The Bridge to Total Freedom, also known as the "Classification, Gradation and Awareness Chart", is Scientology's primary road map to guide a person through the sequential steps to attain Scientology's concept of spiritual freedom. In Dianetics: The Modern Science of Mental Health, Hubbard used the analogy of a bridge: "We are here at a bridge between one state of Man and a next. We are above the chasm which divides a lower from a higher plateau and this chasm marks an artificial evolutionary step in the progress of Man. [...] In this handbook we have the basic axioms and a therapy which works. For God's sake, get busy and build a better bridge!" The current Classification, Gradation, and Awareness Chart is printed with red ink on white paper and hangs as a poster in every Scientology organization. A newcomer to Scientology starts the Bridge at the bottom of the chart and rises through the levels, perhaps reaching the level of Clear, then continuing upward through the OT Levels to higher states of awareness and ability.

The Purification Rundown is a controversial detoxification program developed by Scientology's founder L. Ron Hubbard and used by the Church of Scientology as an introductory service. Scientologists consider it the only effective way to deal with the long-term effects of drug abuse or toxic exposure. The program combines exercise, dietary supplements and long stays in a sauna (up to five hours a day for five weeks). It is promoted variously as religious or secular, medical or purely spiritual, depending on context.

Narconon is a drug education and rehabilitation program founded on Hubbard's beliefs about toxins and purification. Narconon is offered in the United States, Canada and some European countries; its Purification Program uses a regimen composed of sauna, physical exercise, vitamins and diet management, combined with auditing and study.

The Introspection Rundown is a controversial Church of Scientology auditing process that is intended to handle a psychotic episode or complete mental breakdown. Introspection is defined for this rundown as a condition where the person is "looking into one's own mind, feelings, reactions, etc." The Introspection Rundown came under public scrutiny after the death of Lisa McPherson in 1995.

Scientology's internal ethics and justice system is designed to deal with unethical or antisocial behavior. Ethics officers are present in every org; they are tasked with ensuring correct application of Scientology technology and deal with violations such as non-compliance with standard procedures or any other behavior adversely affecting an org's performance, ranging from errors and misdemeanors to crimes and suppressive acts, as defined by internal documents. Scientology teaches that spiritual progress requires and enables the attainment of high "ethical" standards. In Scientology, rationality is stressed over morality. Actions are considered ethical if they promote survival across all eight dynamics, thus benefiting the greatest number of people or things possible while harming the fewest.

While Scientology states that many social problems are the unintentional results of people's imperfections, it asserts that there are also genuinely malevolent individuals. Hubbard believed that approximately 80 percent of all people are what he called social personalities – people who welcome and contribute to the welfare of others. The remaining 20 percent of the population, Hubbard thought, were suppressive persons. According to Hubbard, only about 2.5 percent of this 20 percent are hopelessly antisocial personalities; these make up the small proportion of truly dangerous individuals in humanity: "the Adolf Hitlers and the Genghis Khans, the unrepentant murderers and the drug lords." Scientologists believe that any contact with suppressive or antisocial individuals harms one's spiritual condition, necessitating disconnection.

In Scientology, defectors who turn into critics of the movement are declared suppressive persons, and the Church of Scientology has a reputation for moving aggressively against such detractors. A Scientologist who is actively in communication with a suppressive person and, as a result, shows signs of antisocial behavior is referred to as a potential trouble source.

The term fair game describes policies and practices carried out by the Church against people the Church perceives as its enemies. Hubbard established the policy in the 1950s, in response to criticism both from within and outside his organization. Individuals or groups who are "fair game" are judged to be a threat to the Church and, according to the policy, can be punished and harassed using any and all means possible.

Hubbard and his followers targeted many individuals as well as government officials and agencies, including a program of covert and illegal infiltration of the IRS and other U.S. government agencies during the 1970s. They also conducted private investigations, character assassination and legal action against the Church's critics in the media. The policy remains in effect and has been defended by the Church of Scientology as a core religious practice.

Scientology celebrates seven main holidays each year:

• L. Ron Hubbard's birthday, March 13, celebrates Scientology's achievements during the prior year
• Dianetics Day, May 9, marks the anniversary of the 1950 publication of Dianetics
• Maiden Anniversary Voyage: June 9 is the anniversary of the maiden voyage of the ship Freewinds.
• Sea Org Day is held on August 12
• Auditor's Day is the second Sunday in September
• The IAS event, October 7, celebrates the anniversary of the founding of the International Association of Scientologists
• New Year's event, December 31

A Scientology Sunday service has a sermon, similar to some other religions. It typically begins at 11 am, and Hubbard's writings are read aloud during the service. Like other religions' services, music is played, and sometimes performances are enjoyed. The minister speaks on Scientology doctrine, announces the weekly activities of the community and recent updates from churches around the world. Scientologists also say "A Prayer for Total Freedom", asking the "author of the universe" to help them as they seek enlightenment.

The way Scientology's service has been executed has not changed. The minister chooses from limited possible sermons and group processing exercises. He creates the sermon within a literal interpretation of Hubbard's canonical teachings, functioning similarly to other indigenous theologians who work with canonical texts.

According to religious studies scholar James R. Lewis, Sunday services are for interested non-members, and the holidays and events are for existing members of the church.

The church's rituals can be categorized in four ways: first, rituals performed for spiritual transformation; second, collective ceremonies usually called events, including Hubbard's birthday; third, rites of passage, including weddings and funerals; and fourth, those that mimic Christian rituals, such as Sunday services. Events include the anniversary of Dianetics, the anniversary of Freewinds, and Auditor's Day.

While "Scientology" generally refers to the David Miscavige-led Church of Scientology, other groups are practicing Scientology. These groups, collectively known as the Free Zone or as Independent Scientologists, consist of both former members of the Church of Scientology and new followers of the movement. In 1965, a longtime Church member and "Doctor of Scientology" Jack Horner, dissatisfied with the Church's "ethics" program, developed Dianology. Bill Robertson, a former Sea Org member, was a primary instigator of the Free Zone in the early 1980s. The church labels these groups as "squirrels" in Scientology jargon and often subjects them to considerable legal and social pressure.

On January 1, 1982, Miscavige established the Religious Technology Center (RTC). Shortly thereafter, individuals began splintering off the Church of Scientology and forming groups in what they called the "Free Zone". Most notable was the ousting of David Mayo, Hubbard's own auditor and the highest-ranking technical officer in Scientology whom Hubbard had appointed successor guardian of Scientology's doctrines. After his removal, Mayo established the Advanced Ability Center, which became quite successful until it was bankrupted in 1986 by years of litigation and harassment from the Church of Scientology.

In the mid-2000s, high-profile defectors Mark Rathbun and Mike Rinder represented and stood for the cause of Independent Scientologists wishing to practice Scientology outside of the Church.

• Scientology.org