The documentary claims that private auditing sessions are secretly recorded, including ones with secrets about Tom Cruise.

The "church" blackmails people with their auditing sessions if they leave it.

Auditors manipulate the tone arm during an auditing session to keep the E-meter needle on a marked reference point.

Every morning, Scientologists would be thrown over the side of the ship for errors conducted during their daily auditing sessions.

Most auditing sessions employ a device called the Hubbard Electropsychometer or E-Meter.

But the cost of the auditing sessions, which can run into thousands of dollars an hour, has drawn criticism, as have the church's aggressive tactics toward its critics.

It says information obtained in purportedly confidential "auditing" sessions with a lie detector-like device was used "for purposes of blackmail and extortion."

McMaster had joined Scientology around 1962, having experienced relief of chronic stomach pain after his first auditing session.

Gardner wrote that the "most revealing" material in A Doctor's Report on Dianetics, were the records of the author's own auditing sessions.

But, after hundreds of hours of auditing sessions, he said, "I remember feeling I just wanted it over.