The article deals with three specific aspects of Conan Doyle’s relations to spiritualism: the place and importance of the so-called “psychographies” (or spirit photographies); the logical procedures, worthy of Sherlock Holmes’, that he uses to “demonstrate” that psychographies (and more generally spiritualist phenomena) bear the evidence of a life after death; the use he makes of some discourses proper to the so-called occultist current of the time and to the writings of esotericists, like Swedenborg. By adopting their worldviews he reinforces his own one.