But as disciples have carried L. Ron Hubbard's teachings away from America's shore, the reception has been almost universally chilly at best -- and at times openly hostile.
At one time Scientologists were banned in Australia and forbidden entry to study in England.
Scientology has been shut down in Greece, indicted in Spain, restricted in Russia, rebuffed by Sweden's highest court, expelled from college campuses in Norway, convicted of crimes in Canada and denied status as a charitable organization or a religion in most European countries.
High-ranking Scientologists have been jailed in Italy, France and Spain in connection with what were called crimes associated with Scientology practices, and France keeps Scientology on a list of organizations that need to be monitored for cult activity.
Scientology claims almost 9-million members worldwide, but critics and former Scientologists say membership is far smaller, perhaps as small as 50,000. Scientology says it operates in 129 countries with about 53 offices and 3-million members in Europe.
Scientology's lawyers note that the troubles have come in countries that have no tradition of religious freedom and often in places that have state religions which control the political process.
"It's not so much Scientology practice they have criticized," says Washington lawyer Monique Yingling.
"It's the absence of freedom of religion."
Scientology's willingness to join with other religious groups like Jehovah's Witnesses has helped strengthen religious freedom in some countries.
"As time goes by in each place, we are eventually vindicated," says Mike Rinder, head of Scientology's Office of Special Affairs International. "Every time the church is vindicated and allowed to get on doing what we want to do. We don't like being in litigation and battles with government. We only want to help people through Scientology."
In the United States, Scientology gained status as a tax-exempt religion in 1993 when the Internal Revenue Service agreed to end a long legal battle over the group's right to the exemption. In recent years Scientology, using celebrity members like actor John Travolta, has gained support from members of Congress and other high-ranking officials who have protested the treatment of Scientologists in Germany.
A human rights report issued by the U.S. State Department in late February cited France and Germany as countries that have unfairly discriminated against groups like the Church of Scientology. The International Helsinki Federation for Human Rights had similar criticism in a report issued this month.
Putting down roots overseas has been a difficult undertaking for Scientology:
In 1997 Scientology was shut down in Greece by a court that determined that the Greek Center of Applied Philosophy, the name Scientology used in Greece, had obtained its license under false pretenses. Scientology obtained a license in Greece as a non-profit, public interest organization. Greek courts found it to be a profitmaking group that endangers the mental and physical well-being of its members. Meanwhile Scientology has established a new organization in Greece and continues to operate.
In Greece, Scientology faced complaints from the parents of young people recruited into the organization; they publicly demanded Scientology stop controlling their children. The protest led prosecutors to raid the center and seize documents that were used against Scientology in court in 1996. Among the documents seized in the 1995 raid was a written plan to investigate and discredit a Greek Orthodox priest who has led the charge against Scientology.
In January 1998 a Greek appeals court affirmed the lower court verdict and ordered Scientology's assets liquidated. The court found that Scientology causes a personality change in members and interferes with famility relationships.
In Spain in late 1988, 70 Scientologists, including President Heber Jentzsch, were indicted and hauled off in handcuffs on allegations of fraud, extortion, forgery, tax evasion and violating public health laws. Jentzsch posted $1-million in bail before being released. He has not returned to Spain for trial.
The arrests followed a raid on Scientology centers ordered by a judge who described Scientology as "making quick money under the guise of doing good."
Jentzsch said his arrest occurred because of false information furnished to Spanish authorities by Interpol.
Spanish authorities formally indicted Jentzsch and 17 other members of the organization in 1995 on charges stemming from the 1988 investigation. The charges are still pending.
Scientology officials say they expect the charges against Jentzsch to be dismissed.
In Italy 29 Scientologists were sentenced to jail in early 1997 on criminal charges that included taking advantage of people regarded as mentally weak. The Scientologists were acquitted of tax evasion charges although they have refused to pay taxes in Italy.
In October 1997 the criminal convictions were overturned by Italy's highest court, which ordered a new trial. Scientology lawyers have praised the decision as a landmark for the support of religious freedom.
In France the head of Scientology's center in Lyon was sentenced to jail for manslaughter in 1996 in connection with the death of Patrice Vic, who killed himself by jumping from an apartment building while he was being pressured to borrow money for yet another Scientology course.
The Lyon trial was only the latest battle between Scientology and France. In 1978 Scientology founder L. Ron Hubbard was convicted in absentia and sentenced to four years in prison for making fraudulent claims that he could cure physical illnesses. Hubbard never returned to France to serve the prison sentence before his death in 1986.
In October 1996 three Scientologists were given suspended prison sentences in Marseille on charges that in the United States would have been called tampering with a witness, a cult expert called as a witness during the 1996 trial in Lyon.
In Russia public health officials have outlawed the use of the Purification Rundown and other Scientology practices as a threat to public health. Tax police armed with automatic weapons staged daylong raids on Scientology centers in Moscow in late February. Police said they were looking for everything from tax records to weapons.
Scientology President Heber Jentszch, in a letter of protest to the Russian Embassy in Washington, complained of harassment and said police seized the confidential files of parishioners.
Swiss officials sent three Scientologists to jail in 1998 on fraud and usury charges after a former member complained that he had been bilked out of $80,000 for courses intended to rid him of the "devils" that allegedly inhabited him. The Swiss have also restricted Scientology's use of personality tests as a pretext for recruiting on public streets.
A Swiss security commission report issued in the fall of 1998 questioned the pressure Scientology puts on members to acquire new services and books, intelligence activities against members and critics and attempts to infiltrate governmental positions.
In Germany officials have summarily dismissed complaints from some pro-Scientology Americans who say Scientology is a victim of religious discrimination as well as comparing it with Germany's treatment of the Jews during World War II.
In Denmark Scientology made headlines in 1996 after a young nanny mutilated and murdered the 18-month-old twins of Scientologists. The nanny had a history of mental illness and had stopped taking medication in an effort to gain acceptance into Scientology, which forbids psychiatric care or drugs for its members.
In late 1998 three former Scientologists filed suit in Denmark courts demanding repayment of the money they paid for Scientology courses, saying they were forced into debt to raise enough money to pay for more and more courses.
The two situations have surfaced at a time when Scientology is seeking authority to perform marriages in Denmark.
Canada's highest court in 1997 upheld the criminal conviction of the Church of Scientology of Toronto and one of its officers for a breach of trust stemming from covert operations in Canadian government offices during the 1970s and 1980s.
Scientology also lost an appeal of Canada's biggest libel judgement: $1.6-million assessed by a jury after Scientology tried to discredit Casey Hill, the prosecutor who handled the criminal case against the church.
In upholding the libel verdict, the Canadian court said, "Every aspect of this case demonstrates the very real and persistent malice of Scientology."
Scientology paid Hill more than $4-million in 1996. The payment included interest and attorneys fees.
Before moving its spiritual headquarters to Clearwater in 1975, Scientology operated out of St. Hill Manor, an old castle near East Grinstead outside London. For a time British authorities banned the entry of all Scientologists who wanted to take courses at St. Hill, and Scientology was branded by a court as "immoral and socially obnoxious" as well as "corrupt, sinister and dangerous."
Using its American tax exemption to bolster its argument, Scientology is now trying to gain a similar exemption from the British Charities Commission.
And Scientology continues to battle critics in British courts.
Scientology is also embroiled in a number of civil suits filed in an apparent attempt to silence critics in England. Former Scientologists Bonnie and Richard Woods filed suit against Scientology after the organization hired private investigators to question their friends and neighbors and distributed a leaflet denouncing them. Scientology then filed three libel suits against the Woodses, who live near Scientology's St. Hill headquarters and offer help to members who want to leave.
In mid-1998 Scientology dropped its lawsuits when ordered by the court to disclose some of its secret scriptures. The Woodses' suit against Scientology is scheduled for trial in June.
In bankruptcy as a result of the prolonged litigation, the Woodses now have new attorneys. England's Liberty Panel, the equivalent of the American Civil Liberties Union in the United States, adopted the Woods case and recruited one of London's best-known law firms to represent the couple.
In the Netherlands, Scientology is battling Internet service providers and Scientology critic Karin Spaink over criticism and Scientology secrets that have been posted on the Internet.
Much of the battle is over an upper-level Scientology course that discusses the origin of negative spiritual forces in the world by tracing most human suffering to lingering spirits of Xenu, an extraterrestrial creature who massacred his people over 75-million years ago. Scientologists believe the spirits of the dead attach themselves to people and cause harm unless removed by Scientology training.
Spaink and the Internet service providers won the first round when a judge in 1996 said the service providers could not be held liable for items posted to the Internet and Spaink's Web site did not violate copyright laws because it was "fair use" of materials.
Unsatisfied, Scientology sued again. At a hearing early this month, Scientology asked a court in the Hague to declare Spaink and the service providers guilty of violating copyright laws. A decision is due April 28.
In Sweden Scientology won a $1,250 judgment against a critic who posted Xenu's story on the Internet, but lost the war. The critic, Zenon Panoussis, also deposited a copy of the scriptures with the Swedish Parliament, where tradition demands that records remain open to the public. The Swedish government has sold hundreds of copies of the copyright work for about $50 apiece.
Scientology lost efforts to get Sweden's highest court to seal the record and is unlikely to collect from Panoussis, who has declared bankruptcy and moved to the Netherlands. Instead Scientology is supporting a move to change Swedish law so that copyrights can be better protected.
In an effort to keep the scriptures secret, Scientologists line up outside the Swedish Parliament each day and request the documents so they can keep them from being seen by non-Scientologists.
"They take this very seriously," says Scientology lawyer Monique Yingling.