SK-B: For VN’s admiration of Dickens [...] “We are now ready to tackle Dickens. We are now ready to embrace Dickens. We are now ready to bask in Dickens.”[...] Word-sleuths, -mystics and -fetishists will love VN’s suggested link between “Hyde” and the Greek hydatid (a water-pouch for tapeworms) indicating that Hyde is the 1% parasite dwelling within a 99% “good” Jekyll. But note VN’s firm belief that RLS “knew nothing of this when he chose the name [Hyde].”

 

Concerning Sam Umland's reference to Borges/Fitzgerald: there are various stories by Borges that run in a similar vein with mirrors, splits and doubles. And yet, no one has bothered to quote Nabokov on "doubles": there is a lot about it in "Strong Opinions."

In relation to detectives,mysteries, chess and puzzles , all of them variously explored by Borges, the best is "Death and the Compass".

On doubles, a marvellous one is "Shakespeare's Memory" and "The Other"  -  where one of his selves, the younger one, converses with his old blind self  while reading, and I quote: 

"The Possessed - or, as I think would be better, The Devils, by Fyodor Dostoievsky [...] "The great Russian writer," he affirmed sentenciously, "has penetrated more deeply than any other man into the laburinths of the Slavic soul." I took that rethorical pronouncement as evidence that he had grown calmer. I asked him what other works by Dostoievky he had read. He ticked off two or three, among them The Double."...Suddenly I recalled a fantasy by Coleridge. A man dreams that he is in paradise, and he is given a flower as proof. When he wakes up, there is the flower. I hit upon an analogous stratagem...aso" [ Cf. The Book of Sand and Shakespeare's Memory, translated by Andrew Hurley, Penguin Classics. Another set of good translations into English was recently discussed in the List].