Heimito von Doderer, The Demons (1956)
Okay, so I read this! Let's not pay any heed to how long it took. I mean, I suppose it's not that bad, comparatively, but dude, I read all of Proust (which is something like four times as long) in less time than this. Still, it IS long--this two-volume edition is about sixteen hundred pages, though it's worth noting that that's with a surprisingly large font--with one more like The Man without Qualities, it'd probably be more like thirteen hundred.