Wrote my undergrad thesis on SF and AA (Quentin).
If you're interested:
Faulkner called it his biggest failure. It began as a short story named Twilight (now another short story), with the central scene concerning a young girl climbing up a tree, seeing something that ruined her innocence, while her brothers looked on from below. She had muddy drawers.
Fall of the South, loss of innocence, classical tragedy, it was all there in that image, for Faulkner. But he wanted to be totally objective about it. Totally. That was the modernist enterprise, anyway. So he tried to take subjectivity out of it.
So he wrote Benjy's section, narrated from the perspective of someone without an "I." Then he read it and hated it. Because it didn't tell the full story. He needed something less hectic. And besides, it was still vaguely subjective, as Benjy does have narrative biases.
So he took it the other direction, and wrote Quentin as the most subjective character as possible. And then he read that. And he hated it. Quentin was too romantic. We only see the romance, the beauty of Caddy.
So he wrote Jason. Pure subjectivity, like Quentin, but the polar opposite. Visceral realism rather than romanticism. But then he read it and hated it.
So he wrote Dilsey's section from the third person, focalized on what he thought was a minor character. And that pulled the thing together well enough for him to stop writing.
Some fifteen years later, when his editor was compiling the Portable Faulkner (AILD and SF), Faulkner was asked to write an introduction. Instead, in typical Faulkner fashion, he wrote the Compson Appendix, which he intended to "explain the whole thing." It was intended to go first.
After the first print with the Appendix before Benfy's section, Faulkner requested it be put at the end, because he hated it.
That's why he called it his biggest failure.