"Gregory House goes to OZ" love it! That's exactly what the books are.
Yeah, from reading Stephen Donaldson's website he was pressurised by his publisher to produce 3 more books, but I felt that the last one didn't really end well, and then I was told there were more books, Aparently they were planned all along and complete the 2nd Chronicles.
The first of The Last Chronicles of Thomas Covenant, Runes of the Earth, is a bit rubbish, too much time travel and too much Linden Avery, but the 2nd, Fatal Revenant is better.
I love his writing. I never know what is going to happen. I love how the story twists and turns.
Themes, Hmm. Despair, Love, Good vs Evil. I love how emotional the writing is. I was a bit woeful when I started reading the first books and it just struck a chord with me.