We all know that RVY often was Hubbard's ghost writer, but here is a nice detailed story about it:
CHARLES PLATT was unamazed by Robert Vaughn Young's claim to have ghosted various L.Ron Hubbard writings, including interview responses and the introductions to (though not the main text of) all ten volumes of the dire _Mission Earth_: "When I was pursuing the possibility of a (written) interview with Hubbard for my book _Dream Makers II_, Vaughn Young was the aide I negotiated with. The interview that I received was in Hubbard's style, but I wondered if Young had written it -- because clearly it had been typed on the same typewriter that Young had used in correspondence with me! He claimed that he had merely transcribed a tape from Hubbard. I mentioned these details in my somewhat skeptical commentary surrounding the interview.  To allay my suspicions, I was sent a single-page handwritten letter signed by Hubbard, "authenticating" the interview; and I reproduced this in my book. However, many years later, after Young defected from the Church of Scientology (the highest- level defection ever, I understand) he contacted me via email and told me that I had been correct in my suspicions: He had been the one who wrote the 'Hubbard interview.'"
Source: Ansible, no 157.
("Ansible" is an English magazine / fanzine about Dave Langford (multiple Hugo Award winner). http://www.dcs.gla.ac.uk/SF-Archives/Ansible/
groet, Karin Spaink
-- write, therefore I am: http://www.xs4all.nl/~kspaink