Chamber of Darkness was an anthology of
horror and weird stories, just like many others in Marvel's line of the late 60's - early 70's.
The difference here, however, was that CoD featured all-new material, while the others almost always contained reprints.
(Although this book, too, would start offering a couple of repriints starting in issue #6.) And the
selection of creators here is top-notch - John Buscema, Roy Thomas, Don Heck, Marie Severin, etc. - apparently Stan the Man gave the
extra work to whomever in the stable of writers and artists was willing to take it on. Most notably, in #4 a story called "Sword and
Sorcerers" was basically a try-out for Marvel's upcoming Conan book; it even featured Roy Thomas and Barry Smith as its creators.
Chamber of Darkness would last only eight issues, plus one giant-sized Special; with #9 it would become Monsters On The Prowl.
You can view a gallery of Chamber of Darkness covers by going here