Tom Cruise was introduced by his first wife, actress Mimi Rogers, and has extended the favour to new squeeze Katie Holmes. Actors Patrick Swayze and John Travolta belong, as do Kirstie Alley and Juliette Lewis. Musicians Beck, Sonny Bono and Isaac Hayes are convinced, but Van Morrison, Ricky Martin, Jerry Seinfeld and the two Stones - Oliver and Sharon - have turned their backs on it.
Scientology polarises opinion. It is a belief system conceived in 1952 by prolific American author L. Ron Hubbard, who is viewed as a saviour by some and a con man by others. In 1983, Hubbard's eldest son denounced his father as a fraud, claiming 'Scientology is a power- and money- and intelligence-gathering game'.
The Church of Scientology regards the family as the building block of society and marriage as an essential component. According to his unofficial biographers, however, Hubbard had at least seven children by three different wives and one of his marriages was bigamous.
Critics have labelled the church an unscrupulous commercial organisation that exploits its members. Scientology's principles have been called pseudoscientific by many mainstream medical and psychotherapeutic practitioners, while others frequently describe the church as a cult.
On the flip side, 'there are millions of people around the world who consider they have no greater friend' than Hubbard, claims Scientology.org. There are more than 4,000 Scientology groups, missions and churches globally (the first was established in Los Angeles, California, in February 1954) serving an estimated 10 million followers. The church says it is an applied religious philosophy and a non-profit organisation dedicated to the development of the human spirit. Members claim Hubbard's teachings (called 'technology' in Scientology argot) have freed them from addictions, depression, learning disabilities, mental illness and other problems.
Scientology is 'a study of knowledge'. It comes from the Latin word scio, meaning 'knowing in the fullest sense', and the Greek word logos, or 'study of'. It has been accepted as a religion in some countries, including the United States and Australia, but, in others, it is considered a business or a totalitarian sect.
Inspired by the want and misery he experienced in Asia, Scientology's doctrines were maintained by the well-travelled Hubbard until his death in January 1986, as he sought to reveal the true nature of man.
Scientology also covers ethics and morality, well-being, communication, marriage, raising children, dealing with work-related problems and educational matters. It rejects homosexuality as a perversion and views mental-health professionals and the drugs they prescribe as fraudulent and oppressive.
In 1966, Hubbard told Scientologists, 'We want at least one bad mark on every psychiatrist in England - a murder, an assault or a rape or more than one.' He committed the church to eradicating psychiatry in 1969, announcing: 'Our war has been forced to become, 'To take over absolutely the field of mental healing on this planet in all forms'.' Perhaps, then, it's no surprise Scientology has taken hold most visibly in Hollywood, where few non-believers shrink from the 'evils' of the psychiatrist's coach.