Harry Houdini and his exposure of the fraud spiritualist, spirit photography, spirit slate writing, ectoplasm, clairvoyance, and other quakery and cons perpetrated on the gullible, by the likes of the Boston Medium Margery, the Davenport Brothers, Annie Eva Fay, the Fox Sisters, Daniel Dunglas Home, Eusapia Pallandino, and other con artists of their ilk.