I like lots of the stuff that's been recommended so far - Elric, the Book of the New Sun, Vance (the Demon Princes series is maybe my favorite), George R.R. Martin, Iain Banks, Terry Pratchett.
Some favorites that haven't been mentioned yet:
- the Fafhrd & the Gray Mouser stories, by Fritz Leiber. I like that KotC doesn't have thieves (neither does the 1974-edition D&D game I run in NYC - drop in if you're in town), but Lankhmar's Thieves Guild is pure awesome.
- Hugh Cook's Chronicles of an Age of Darkness. Paizo's Planet Stories is reprinting The Walrus & the Warwolf, but I've been able to find the first three (published in the US as four books) at
Paperback Swap and they're probably even easier to find used if you're in the UK. I love the density of invention in these books, and the mix of cruelty and empathy; they remind me of Vance without being derivative.
- Nifft the Lean, by Michael Shea. Also similar to Vance, but with more of a horror writer's sensibility - the descent to the underworld is unforgettable. Later books in the series are worthwhile but this is the one that'll hook you.
- Bridge of Birds, by Barry Hughart. Comic fantasy in a China that never was; like an impossibly great game of Oriental Adventures D&D.
The
Grognardia blog has been reviewing a lot of the books that were either specifically cited as influences on D&D by Gygax, or other examples of its pulp fantasy roots. I love reading Grognardia, and the book reviews are part of the reason why.