The key skill that Hubbard had and utilized to the nth degree was in taking all of the best writings he could copy/paste from, throwing them in a bowl and extrapolating out all the best of which that he could take sole credit for.
Add on the results of the special research assignments he gave to his followers, like the late Dillard "Bud" Eubank, who introduced him to Mary Sue, who told me how the entire 0 to IV grade chart was subbed out by Ron to a team of guys with a great cross spectrum of psychic/psychological training and experience in many of the "other practices" we were forbidden to participate in for the purpose of removing obstacles to clearing and came up with the grades that he claimed to be sole source of. Dillard said "we decided that it was for the greatest good that we all went along with it and kept quiet about it no matter who's ego got trampled upon".
Supposedly, and Hubbard gave some credit to him on occasion, Count Albert Korzybski and his General Semantics which had key elements that were morphed into some of the early Dianetics concepts but as I've never read it, I don't know the details.
Then through a whole lot of faked case histories, books like Dianetics came out along with his faked credentials and a "new science of the mind" was born only to die on the vine a few years later involving Don Purcell and he went on to crap out Scientology, the science of knowing how to know but not when to know it as the knowledge always seemed to come at a time it was no longer relevant, often to merely foster regrets - HA!
Never have I seen so much made of so little.