I just re-read this thread, and there was a fair bit of negative comment that Hubbard's work was all just thinly veiled propaganda for his cult. I don't think this is right, and if anyone's interested in reading LRH, his older golden-age SF predates his scientology invention. He came up with 'dianetics' as a physiological tool very early in his career (believing in it as a holistic self-help methodology, along with others such as Campbell), but he made no link to religion or Scientology until 1951. His golden-age work is therefore untainted by his wish to increase any revenue from Scientology, as the cult didn't yet exist. He was undoubtedly one of the big names in golden-age SF, often taking the cover on magazines of the time. I've not read his earlier work myself much, apart from the occasional short story, but I'd happily do so.
For clarity - 'Dianetics' was first published by Hubbard in 1950, and his 'church' wasn't founded until 1952 (following bankruptcy in '51), but he published the majority of his SF between 1938 and 1949, and Typewriter in the Sky (perhaps his most famous novel) was published in 1940, twelve years before he conceived of the 'religion'.
For further clarity: I'm not a Scientology apologist, I think they're all nutters.