"Our Lady of Darkness" modern horror novel
 

For a very chilling modern horror novel that also dips into the Lovecraftian tradition, let me recommed the late Fritz Leiber's "Our Lady of Darkness". This was first serialized in F&SF as "The Pale Brown Thng" (featuring a very unsettling cover illustration) then expanded and printed as a novel.

I lived in San Fran at the time and some of the locales in the novel are real, accurately described, including an actual run-down residence hotel. A pal of mine jokingly recommended that I get a room and stay there overnight, and my response was "No Way!"

"Our Lady of Darkness" by Fritz Leiber may now be out of print but it's worth looking for, a genuinely scary but very urban-themed supernatural horror novel.