A definition of Scientology is hard to pin down. Basically, it's a system of beliefs, teachings and rituals originally established as a secular philosophy by L. Ron Hubbard. His 1950 book Dianetics: The Modern Science of Mental Health, provided the core principles of what would later become Scientology.
Scientologists regard the publication of the book as a seminal event, and celebrate its publication date -- May 9, 1950 -- as a religious holiday.
A central belief of Scientology is that a person is a mortal, spiritual being (called a "thetan"), basically good, and has lived through many past lives.
The ultimate goal of Scientology is "true spiritual enlightenment and freedom for the individual." Stored memories of Thetans' past lives can cause problems in the present.
Scientologists believe that the "reactive mind" (the portion that works on a totally stimulus-response basis, not under the control of the individual) commands one's awareness, purposes, thoughts, body and action. Through counseling called "auditing," Scientologists believe they can reduce and ultimately erase the power of the reactive mind, a source of irrationality, fears and nightmares. Before a person is audited they are considered "Pre-Clear."
Those that reach the higher teachings called OT (Operating Thetan) III, a state of being beyond the initial "Clear" state, within the Church of Scientology are said to learn about Xenu, the intergalactic ruler who implanted thetans, or alien spirits, in Earth's volcanoes 75 million years ago. But details of teachings at these higher levels are sketchy.
Since it was founded in 1954, Scientology has grown to include more than 5,100 churches, missions and groups in 156 countries.
Symbols of Scientology include an eight-pointed cross and an "S" between two triangles.
Celebrated holidays include Hubbard's birthday (March 13), the date of Dianetics' publication (May 9) and Auditors' Day (second Sunday in September).
Scientologists are opposed to mind-altering drugs, psychiatry and psychiatric drugs. Narconon is Scientology's drug rehab program. Treatment includes an intensive program of running, massive doses of vitamins and very long sauna sessions designed to "run out" drugs and radiation from the body.
Some of the celebrities identified as followers include Tom Cruise, John Travolta, Kelly Preston, Kirstie Alley, Isaac Hayes, Chick Corea, Lisa Marie Presley, Jenna Elfman and Ann Archer.