Greetings!
"SLAVES TO DARKNESS"--1988; and "THE LOST AND THE DAMNED"--1990
LINK:
http://en.wikipedia.org/wiki/Realm_of_Chaos_(Warhammer)
Yes. A thousand times yes! These two ancient volumes--long out of print, extremely rare, and I have heard can easily be sold for *hundreds* of dollars, *each*--are each like a nuclear shark covered in chocolate sauce ripping into your brains and inspiring you like some crazed maniac for weeks and months at a time with campaign ideas, adventure ideas, concepts for NPC's, lots of different stories and backgrounds, plots, sanity-blasting mutations and horrid, delicious inspiration for thousands of new creatures, as well as epic stories and adventures, and well, lots of mind-blowingly cool monsters that you will stay awake hours into the deep of night feverishly--and gleefully--converting to the D&D system of your choice...yes, you will laugh and shriek maniacally as a new day dawns on your hapless and smug players...
--for now, within your blood-soaked, defiled hands, lie the keys to unlocking absolute creative genius and oceans of inspiration for your campaign, even if it is at the risk of shredding and warping your sanity-blasted psyche and casting your mortal form into the seas of Chaos...yes, my friend...you, too...will know it is all worth the journey...
BLOOD FOR THE BLOOD GOD!!!
LOL.

Well, my glowing, crazy hyberbole aside, the books really are special. I own both of them. They are truly brilliant, flavourful and awesome. I highly recommend them, for you will treasure them both. Yes, even though you will have to do the leg-work of creating stuff for your campaign, just reading the twisted stuff in these books along the way is a real treat. And, I might also add, you know the old saying, "A picture is worth a thousand words!"?--well, these two books are illustrated in ways I don't think artists nowadays can even comprehend. The books are masterfully illustrated with such wicked inspiration, that yeah, just you casually flipping through the black and white illustrations will have your mind literally spinning with ideas, and you'll no doubt feel yourself mutteirng at every picture or two..."Damn...that's wicked..."Whoa, man...so cool...lots of ideas here...wow, what the eff is going on there?...Hmmm...damn, that's just bizarre and so awesome..." and so on. They're that kind of level of inspiration.
Get them, my friend, if you can. Even at $100 dollars each, and more, they are worth it. They are, in so many ways, unique, and incomparable. You can search back the TWENTY YEARS since they were both published, and there's never been anything nearly as inspiring when it comes to similar monster material.
Semper Fidelis,
SHARK