I think a lot of people are getting the wrong idea when they call Tolkien a freak because he invented this elaborate framing device whereby the Red Book of Westmarch was actually written by Bilbo and Frodo (with some addenda by Sam) and he, Tolkien, was merely an editor and translator. Throughout history it’s actually been a very common literary device for an author to represent their work has having been written by a character who appears in the story, with the author themselves variously positioned as a translator, editor, and/or literary executor. At the time that Tolkien was writing, such a device would have been seen as somewhat old-fashioned, but certainly not eccentric. Like, Tolkien was definitely a freak, but not for that reason.
My favorite example of this is Frankenstein.
Imagine you Margaret Saville, living in comfortably in Victorian England. Your brother will be back from his expedition to the north soon. And then the afternoon post arrives and you get a novel’s worth of delayed mail from aforementioned brother. And he writes about how they found a crazy, kinda cute, guy out on the ice of the North Pole. And the crazy guy tells your brother his life story, which your brother then takes notes on (and mails to you for some reason).
So now you’re reading the incredibly detailed notes from your brother about the life story of a crazy guy from the ice. After skimming through multiple chapters detailing the youth of a crazy guy you don’t know, you read something about constructing a living man out of the pieces of a corpse? and it’s fluent in French? So you keep reading and at one point of the account the Corpse tells Crazy Ice Guy what it’s been up to.
So now you’re reading your brother’s incredibly detailed notes about the story told by Sad Crazy Guy, in which an articulate Corpse is now telling a story about living in a poor family’s walls and watching them (which is how it learned French btw). And then the Corpse overhears the villagers tell the story of how they became impoverished.
So now you’re reading your brother’s shockingly detailed recording of the Hot Crazy Ice Guy’s ramblings about the Frech-speaking Corpse’s account of some random Villagers’ story about how they were betrayed by the Turkish merchant they broke out of jail back in Italy that one time.
And then your brother walks in the front door and you’re like Robert What The Fuck Is This?