After serving in World War II, writer L. Ron Hubbard published a series of articles and then a book on what he described as a new approach to mental health. "Dianetics: The Modern Science of Mental Health" was first published in 1950, and it quickly became a best-seller. In 1954, Hubbard founded the Church of Scientology. Gilles Bassignac/Gamma-Rapho/Getty Images

Hubbard and his children in December 1959. They are testing a device called an E-meter, which Scientologists say measures the body's electric flow as an auditor asks a series of questions that they say reveals sources of trauma. At the core of Scientology is a belief that each human has a reactive mind that responds to life's traumas, clouding the analytic mind and keeping us from experiencing reality. Chris Ware/Keystone Features/Getty Images

Hubbard works in his greenhouse in December 1959. Chris Ware/Keystone Features/Getty Images

Hubbard in the south of France in May 1968. L. Ron Hubbard Library/AP

Hubbard talks with reporters in his office in 1974. Many groups and individuals have challenged Scientology's legitimacy as a religion. Scientologists have faced opposition from the medical community over the religion's claims about mental health, from the scientific community over its claims about its E-meters and from other religious groups about its status as a religion. Keystone-France/Gamma-Keystine via Getty Images

Hubbard poses for a portrait in New York in January 1982. He died in 1986. Michael Montfort/Michael Ochs Archives/Getty Images

The entrance to the Los Angeles headquarters of the church in March 1998. DPA/Landov

Confetti rains down as actor Tom Cruise, left, embraces David Miscavige, the leader of the Church of Scientology, at the opening of a new church in Madrid in September 2004. Cruise is one of the world's most prominent Scientologists. "What I believe in my own life is that it's a search for how I can do things better, whether it's being a better man or a better father or finding ways for myself to improve," Cruise told Playboy magazine. "Individuals have to decide what is true and real for them." Paul White/AP

Miscavige speaks during the inauguration of the Madrid church in September 2004. Pierre-Philippe Marcou/AFP/Getty Images

Scientology made headlines in June 2005 when Cruise got into a heated debate with "Today" host Matt Lauer over psychiatric drugs. The Church of Scientology's website says that "the effects of medical and psychiatric drugs, whether painkillers, tranquilizers or 'antidepressants,' are as disastrous" as illicit drugs. Virginia Sherwood/NBC/AP

Actress Kirstie Alley and actor Tait Ruppert perform during the Church of Scientology's Christmas Stories XIV benefit in December 2006. Frazer Harrison/Getty Images

A volunteer from the Church of Scientology touches an injured woman in Port-au-Prince, Haiti, after the devastating earthquake there in January 2010. Thomas Coex/AFP/Getty Images

An E-meter sits next to Hubbard's book "Self Analysis" in Zurich, Swizerland, in January 2011. Alessandro Della Bella/Keystone/Corbis

Actor John Travolta and his wife, actress Kelly Preston, attend the opening of a Scientology Mission in Ocala, Florida, in May 2011. Michael Doven/Getty Images

A headquarters for the Church of Scientology is seen in Clearwater, Florida, in January 2013. Edward Linsmier/Getty Images