Astounding: John W. Campbell, Isaac Asimov, Robert A. Heinlein, L. Ron Hubbard, and the Golden Age of Science Fiction

by Alec Nevala-Lee

he was overheard saying that the best way to make money would be to start a religion—although the legend that Heinlein bet him that he couldn’t is undoubtedly apocryphal.

I doubt it's apocryphal.