H.P. LOVECRAFT - THE DREAM-QUEST OF UNKNOWN KADATH (FINISHED 1927, PUBLISHED 1943)
Lovecraft was best known for his horror stories, which are still referenced by heavy metal bands and adapted by filmmakers 71 years after his untimely death in 1937. Although I'm a huge fan of that stuff, I actually prefer the 'weird fantasy' he penned earlier in his career. 'The Dream-Quest of Unknown Kadath', a novella he wrote in the mid-to-late 20's, is arguably his best fantasy piece, which unfortunately wasn't published until 6 years after his death.
'Dream-Quest' documents the travels of lucid dreamer Randolph Carter (a recurring character in the Lovecraft mythos), and his epic quest "beyond the wall of sleep" to locate the mystical Sunset City. On his way, he encounters strange, sentient rodent-men, ghouls, night-guants, and evil space pirates who capture slaves to appease their evil masters, the hideous Moon-Beasts. My favorite elements of the story are the benevolent talking cats of Ulthar, who bail Carter out of more than one jam.
Lovecraft had an affinity for cats in real life, describing them thusly: "For the cat is cryptic, and close to strange things which men cannot see. He is the soul of antique Aegyptus, and bearer of tales from forgotten cities in Meroe and Ophir. He is the kin of the jungle’s lords, and heir to the secrets of hoary and sinister Africa. The Sphinx is his cousin, and he speaks her language; but he is more ancient than the Sphinx, and remembers that which she hath forgotten."
<--Lovecraft with Ultharian denizen (and catnip enthusiast) Felis.
The story is whimsical, reminiscent of the works of Lord Dunsany and Edgar Rice Burroughs, but at the same time dark, concerning the Great Ones (forgotten Gods of Earth) and the Other Gods (lords of space, led by evil king Azazthoth and Nyarlathotep, "the crawling chaos"). If you like your fantasy tinged with horror (or vice versa), 'Dream-Quest' truly satisfies, and if you aren't yet familiar with the work of this brilliant hermit, this book is a good place to start.
Howard Phillips Lovecraft, 1890-1937. R.I.P.