Voss Eldridge is an investigator of parapsychological phenomena, and on the whole is rather hard-headed about it all, not even believing that there’s anything to it himself. (This is something which meets with the general approval of the supremely rationalist Black Widowers.) And yet, he is aware of an incident which he cannot explain without resorting to the paranormal, despite all the intricate and interesting solutions offered by the Black Widowers, and Henry alone is able to penetrate Eldridge’s story and discover the truth.
This is story is the supremest kind of cheat in a mystery, but I don’t care—I love it anyway. The solution is that Eldridge is lying and making the whole thing up as he goes along (which gives it a certain affinity to “Truth to Tell”), which is why it’s a cheat—an armchair detective story such as your typical Black Widower story depends on assuming that the person narrating the circumstances is telling the truth. A puzzle is being laid out for the reader, and for the reader to have a fair chance of solving it, they should be able to assume that there is a legitimate solution based on the facts presented.
Nonetheless, Asimov has the gall to turn this assumption on its head. In his afterword to the story in Tales of the Black Widowers, he admits that the solution may be seen as unfair, but defiantly sticks to his guns. And he gets away with it, in part because it offers him—a supreme rationalist himself—a sharp kick to the groin of believers in the paranormal. And the solution is so neat and pleasant one cannot help but forgive having been lead down a series of wrong paths for so long. It’s a nicely done job.