It's odd - I'm almost sure I've never read this before, but of course I know the story. Everyone does. The afterword notes this, saying that over 90 films have been made, which seems like a ridiculous amount to me but would certainly explain the cultural creep. And it's such a good idea, if not perhaps entirely original... the evil in a person split off, transformed into its own personality. The transformation, of course, is not truly absolute - Jekyll presents as a good person, but that is largely affectation, as he's prepared to indulge the part of himself that is Hyde, even knowing the effects it will have on other people. It's more separation than transformation.

Regardless, as I said: I was almost sure I hadn't read this before, so I decided to make an end to uncertainty. Having read it, I'm even more certain. It certainly wasn't what I expected and I think I would have remembered that undermining of expectation. I liked it, but I liked the image of what it was better, if that makes any sense. It's a fractured, elliptical sort of story, told from multiple perspectives, not all of which are entirely trustworthy. The text's an exercise in reading between the lines, which is interesting, but it's also a little bit duller than I thought it would be, a little bit muted, and more than a little repetitive, which I suppose is what happens when several people recount shared experiences from their respective different points of view. But it also has the great virtue of being short, with a good deal packed into relatively few pages, and I always appreciate that.