Hubbard published "Dianetics," the precursor handbook to Scientology, in 1950. Legend has it he had a bet with science fiction writer Arthur C. Clarke that he could start a religion and get rich. Whether or not the bet really happened, Hubbard did both. Heinlein was writing at the same time but "Moon" wasn't published until 16 years later, in 1966.
Correction: "Stranger in a Strange Land" was published in 1961. The date for "Moon" is correct -- I just got the titles switched in my head.