The conceit of this short anthology is to re-examine many classic horror stories—from novels, movies, stories, and [in one case] biography—with an added dash of pain. To re-examine them, in very quick form (a page or two, a handful paragraphs), with an element of keen insight into the humanity of the characters.
Generally speaking, many of them deal with loneliness, broken hearts, and betrayal. The semi-titular tale depicts Frankenstein's corpse being used in a similar-to-his-own experiment, with the added twist that he knows the being closest to him in nature—the creature of the original novel—is no more, so he is denied true kinship. In a riff off of H.P. Lovecraft's "The Outsider", the Outsider returns to his grave and by the time he wakes up, again, to see if things are better finds he has outlasted all life on earth. With an added bit about why we might be dissatisfied by what we see in the mirror. That is the sort of thing to expect.
The whole thing, a few dozen vignettes, takes up about as much space as a single novella, and can be read reasonably in a sitting. It covers many of the best known classic monsters: Dracula, Frankenstein (the scientist, not the creature), Dr. Jekyll and Mr. Hyde, The Wolfman, Dr. Moreau, The Phantom, the folk from The Turn of the Screw, a few from Poe and Lovecraft, and so on. If you are a horror fan, you will probably recognize all or nearly all.
Standout stories would possibly be the ones mentioned above, as well as Ligotti's addition to Turn of the Screw [which is where his humor shines brightest/darkest] and the extended life of Thurston beyond "Call of Cthulhu". There a plenty of other moments worth noting, but there are also lots of moments worth taken as something like background "hmmm". The very last story differs the most because it is about Lovecraft as a non-fictional character, and deals with something like a final overcoming of pain at death, but I suppose that is up for debate.
Special attention should be given to Harry O. Morris's artwork throughout. They are exemplary, and add considerable flavor to the book as a whole. If you are lucky enough to get ahold of a Centipede Press edition, that is.