'Going Clear' on Scientology: Inside the Mysterious Church Popular in Hollywood

— -- Power Players

While it boasts of membership from Hollywood’s A-list, including Tom Cruise and John Travolta, the inner-workings of the Church of Scientology remain largely a mystery to onlookers. But a new HBO documentary claims to expose the church's secrets through accounts of former members.

Much like the faith it seeks to demystify, “Going Clear: Scientology and the Prison of Belief” has spurred a wave of controversy in the wake of its explosive allegations about life inside the church, its practices, and its deceased founder: Science-fiction author L. Ron Hubbard.

Author and journalist Lawrence Wright, who wrote the book upon which the film is based, sat down with “Power Players” at the Four Seasons Hotel in Washington, D.C., for a discussion on the belief system and founding origin of Scientology.

“The idea is that it's a step-by-step ladder to spiritual enlightenment, and if you follow the techniques ... you will purge your mind of fears and neuroses,” Wright explained. “Then, you'll be enlisted in this cause, which is to clear the planet, to save the planet and keep it from destroying itself.”

In the film, former members of the church explain how the introductory principles of the techniques initially drew them to the religion. But in progressing up the “ladder to spiritual enlightenment,” one former member -- Academy Award-winning film director Paul Haggis, who spent 35 years in the faith -- recalls being presented with a head-scratching theory about the origin of the Earth.

“They gave him a locked briefcase, which he lashed to his wrist, and went into a room that was locked. And then he opened up the briefcase, and inside -- in Hubbard's handwritten script -- is the story of the origin of the universe, which is the Xenu story of a galaxy far, far away, back in time,” Wright said.

“People were shipped on airplanes ... dropped in volcanoes and blown up with hydrogen bombs.”

It was a turning point for Haggis. “Paul read it, and thought, ‘What?’” Wright recalled. “It occurred to him that this is an insanity test, and, ‘If I say I believe it, they'll think I'm insane and kick me out,’ but it turned out that that wasn't true.”

Upon Hubbard’s death in 1986, Wright explained that one of his leading disciples, David Miscavige, “wrestled control of the church.” His leadership has been controversial, with some former church leaders claiming he slapped or punched them. A number of those alleged episodes are described in Wright’s book and in the HBO documentary.

Nevertheless, the church continues to be held in esteem by many prominent Hollywood actors. And it’s in part because of the star power of Travolta, Cruise and others, that Wright believes the church has been able to maintain an air of legitimacy.

“L. Ron Hubbard understood that America really does worship ... celebrity. The idea that famous people are associated with this church adds credibility to it. And it makes people think that Scientology must be responsible for their success,” explained Wright.

In response, the church has produced a series of online videos disputing many of the claims in the book "Going Clear" and in the movie.

In a statement to ABC News, the church said the book is "grossly inaccurate" and the movie is "bigoted propaganda." The allegations that Miscavige struck people are "false," the church said, and come from a small group of dishonest former members who were ejected from the church for misconduct.

The statement goes on to say that allegations that L. Ron Hubbard inflated his injuries in World War II are "false" and Wright's characterizations about Scientology are "inaccurate."

An encore presentation of “Going Clear: Scientology and the Prison of Belief” airs Monday, March 30, at 9 p.m. on HBO.

For more of the interview with Wright, watch this episode of “Power Players.”

ABC News’ Jordyn Phelps, Gary Westphalen, Tom Thornton, Pat French and Pat Glass contributed to this report.