EX-Scientologist John Duignan has hit out at the religion, claiming actor Tom Cruise was freely allowed to have a child out of wedlock, but sex is banned outside marriage for ordinary members.
In his book, titled In The Complex, he claims the Church, invented by former science fiction author L Ron Hubbard, regularly orders women to have abortions .
And he claims most members are banned from eye contact with more famous members.
John, who was a member for 22 years, said the world's fastest growing cult often recruits members using a personality stress test.
He said it has fantastical secret beliefs - which can be read on the internet - a caste system, brainwashing techniques, and relies on interrogation and forced manual labour to help enforce discipline.
John added that so-called upper level Scientologists are promised they will regain powers they once had as an immortal spiritual being and gain the ability to travel through space and time.