Donaldson gets first mention. And when I saw it on FB, the LFB cover was pictured.
It's interesting that the "fallen out of favor somewhat" hyperlink is a fairly positive review of the Final Chronicles.1) Stephen Donaldson
When you talk about works that brought a new darkness to fantasy, it's hard to overlook Lord Foul's Bane, the 1977 bestseller that launched Donaldson's Chronicles of Thomas Covenant series. Donaldson took all of the tropes of J.R.R. Tolkien and C.S. Lewis, and peered at them through an ugly light. And he gave us a protagonist that it's almost impossible to sympathize with, especially in the first book. Thomas Covenant is a self-loathing writer who's become a pariah after he's infected with leprosy — so when he goes to a fantasy world where he's hailed as the mythical savior, the first thing he does is to rape someone. And then he carries on being the hero of the series, slowly coming to invest in the reality of this strange fantasy world. Not surprisingly, this series has fallen out of favor somewhat — but it still deserves a place in the history of fantasy that challenged our heroic ideals.
And it's funny to me how people (like in the comments) catch on fairly easily to the whole 'doesn't believe the Land is real' aspect but almost never seem to mention how that's such a huge threat to Covenant's health, psyche, or even his soul. Yes, on one hand we're all supposed to get how most sane people would react to that kind of situation (not us, of course; most of us wear white gold rings for just such an occasion). But more importantly, Covenant isn't most people. There's a reason he has leprosy instead of asthma... or even cancer. He's the anti-us. Until he isn't.