Lafayette Ronald Hubbard published Dianetics: The Modern Science of Mental Health in 1950. According to Bridge Publications, itself an arm of the Church of Scientology, at least 80 million copies have been sold.

That sounds possible, if you credit the church’s claim that it has 8 million members. But then you have to reckon with more objective external estimates that the membership might be just 50,000, while one assumes that the book sales are inflated by deliberate bulk-buying by church members. So what are you going to believe?Here’s a quick experiment. Amazon ranks books according to their current sales. I thought I would compare Dianetics with Ayn Rand’s Atlas Shrugged.

The Rand novel was published in 1957 and it apparently has a devoted readership eager to believe in the free mind solving all problems. My experiment was conducted on 20 January 2013. The hardback of Atlas Shrugged was then ranked 62,059, the Kindle edition at 976 and the paperback at 416.

I was surprised and impressed, but I’ve seen people on buses, in parks and at the beach reading Atlas Shrugged. I have never seen anyone reading Dianetics, and this might be why: the hardback is ranked at 402,370 and the paperback at 24,618. There isn’t a Kindle edition, but the audio book is ranked at 318,283.