“A Study in Scarlet is interesting, but not good on Mormons. ACD was not very friendly to religions other than his. The “Piltdown Man” still cracks me up, though. That was a famous hoax he perpetrated.
I think Piltdown Man was a famous hoax ACD (and Teilhard de Chardin) fell for, rather than perpetrated. ACD was a real flake in a lot of ways. He’s a recurring character in the “Murdoch” mystery series.