Stephen King’s The Wind Through the Keyhole has a frame story that ties into the action of the Dark Tower series (between books 4 and 5). Within that frame story nests two more stories, one that features Roland Deschain as young gunslinger and one nested within that story that features the teenage Roland telling another story from several centuries before — a story that his mother had read to him when he was a child.
I was skeptical of this set up. But after reading it, I think it works quite well.
For one thing, it provides a richer sense of history. Each layer goes deeper in back in time so we experience the land in an earlier states of progressively less decay (although the falling apart still happens in the middle one). This provides the reader with a greater sense of the loss that is playing out in the main plot line of the Dark Tower series. King emphasizes this by making the middle story more fairy tale-ish. What is interesting, though, is how he uses the particular details of his worldbuilding — the use of High Speech, the presence of gunslingers, the Beams, North Central Positronics — throughout all the three stories so that the fairy tale-ness of the middle story isn’t quite as distant. There is sense that we’ve back in time to a different place, but one that’s still part of the world. This continuity ties the stories together in an effective way.
But what makes The Wind Through the Keyhole really work is how it illuminates Roland’s character. The fact that he chooses to tell the particular story that he does (as he and his ka-tet hole up during a devastating storm) and that that story includes a younger him telling a particular story all says something about who he is and what he finds interesting and scary and what he values. I can’t go into detail without major spoilers so I’ll say only this: storytelling reveals characters. These stories are both told by and are about Roland and are that way in a way that feeds directly into the events that haunt him and drive him.
Considering the meta-fictional turn the Dark Tower series takes in the latter part of Wolves of the Calla (a turn, incidentally, that I didn’t really like for all that I’m a fan and student of meta-fictional and experimental fiction), I was leery of the playing with narrative that takes place in The Wind through the Keyhole. I’ve rarely been quite so happy to be wrong in my pre-judgment of a novel.