The Mask of Cthulhu (1958) by August Derleth, containing the following stories: "The Return of Hastur" (1939); "The Whippoorwills in the Hills" (1948); "Something in Wood" (1948); "The Sandwin Compact" (1940); "The House in the Valley" (1953); and "The Seal of R'lyeh" (1957).
August Derleth's Lovecraftian stories can send some people into a rage. The rage seems to stem from Derleth's attempt to recast the Cthulhu Mythos (a term which he coined, not Lovecraft) as a conflict between Good and Evil. Lovecraft's Cthulhu Mythos stories generally suggested that the ancient aliens/gods that threatened humanity were amoral, not immoral: basically, they just wanted their universe back, and humans were the ants that were getting in the way.
So it goes. A lot of writers have continued in the Derlethian vein of Cthulhu Mythos, though -- among them, Brian Lumley, Lin Carter, and Colin Wilson. It's a subset of Lovecraftian horror, and one that's no more or less legitimate than the far larger school of Lovecraftian horror that ends every story in absolute despair and defeat for humanity. Lovecraft's Cthulhu Mythos stories ended with humanity still hanging in there, somehow, though his protagonists often took it in the chin. Both schools diverge from Lovecraft's vision, then.
But as to this collection of some of Derleth's wanderings in Lovecraft-land. Well, Derleth was superior to Lovecraft in at least one aspect: his depiction of rural life. His small towns and the countryside around them generally seem fairly believable, and his rural dialects aren't absolutely bananas the way that Lovecraft's forays into self-invented rural dialect in stories that include "The Colour out of Space" and "The Dunwich Horror" tend to be.
Beyond that, there's a sort of comforting nature to Derleth's Cthulhu Mythos stories. His monsters aren't particularly scary. Indeed, he goes to the well of the Deep Ones (from Lovecraft's "The Shadow over Innsmouth") so many times in his stories that they lose all capacity to shock.
So, too, one of Derleth's preferred narratives, in which a person moves into a house or a region and subsequently either gets possessed by ancient, resident evil or at least severely threatened by it. Five of the six stories in this volume follow that pattern; there are an awful lot of the same type of story throughout the rest of Derleth's work as well. It's an interesting psychological obsession: Derleth, working in someone else's milieu, again and again writes about people who end up... working in someone or something else's milieu. Lovecraft himself used this plot on several occasions, though not nearly as many times as Derleth did -- and in Lovecraft's case, the affected parties are related to the ancestors who plague them in the present.
The one story here that doesn't follow this pattern, "Something in Wood," instead has its doomed character gradually possessed by a statue of Cthulhu. I guess we're really six for six in this vein, aren't we? This subset divides into two categories: people who are related to previous occupants of the house and people who aren't. The subset that cuts across these are people who are overwhelmed by the evil in the house and people who defeat it.
Another thing that happens several times in the collection is a scene in which it's discovered that someone has vanished somehow from inside their clothes, leaving an empty outfit on the floor or on a chair as if they'd been sucked right out of it. It's a nice image when used sparingly. I enjoyed these stories, though they're not frightening and some of the breathless, italicized concluding paragraphs seem almost intentionally self-parodic. Recommended.

Ghosts Know by Ramsey Campbell (2011): What initially seems to be a horror novel soon turns into a murder mystery, with prickly first-person narrator Graham Wilde both the amateur investigator and the prime suspect. Wilde, the host of a Manchester call-in radio show when the novel opens, soon finds himself drawn into the world of "psychic investigators" and into the mysterious disappearance of a female teenager, Kylie Goodchild, who was ostensibly trying to track down Wilde on the night she disappeared.
Wilde's painful childhood has left him with anger-management issues that flare up verbally at unfortunate times. But he's also rightfully angry at a self-proclaimed psychic who inserts himself into the police investigation -- and then points the finger at Wilde, who's become a vociferous critic of such psychics. Wilde demonstrates on a couple of occasions the tricks people such as John Edward use to "read" an audience. And the psychic here, Frank Jarvis, turns out to be an especially odious charlatan whose tricks, Wilde believes with mounting frustration, should be transparent to all.
Campbell's use of first-person narration is solid here, and periodically leads us to question how much we actually trust Wilde and what he's telling us. Such narration also leads to a slightly different narrative voice for Campbell, whose off-beat descriptions of things have to be tailored to his narrator's relatively straightforward way of observing the world. Wilde is much more verbally inclined than he is to the visual, which makes perfect sense given his job.
The mystery aspect of the novel plays scrupulously fair with the reader. It helps, of course, to realize this is a murder mystery, but once one goes back to the relevant earlier sections of the novel, upon the revelation of the culprit, the whole thing has indeed been laid out fairly. There's a decent helping of humour here, both bleak and not-so-bleak. Wilde's callers sometimes seem to be completely addled, while Wilde, when angered, sometimes verges on Yosemite Sam-level outrage that he can barely contain.
As with many of Campbell's works, this one deals in large part with the scars, physical and psychic, of childhood, and the ways in which they have shaped the adults the children become. And one last twist towards the end of the novel comes like a kick in the stomach. Highly recommended.

The Watchers Out of Time by August Derleth and H.P. Lovecraft (Collected 1974): Besides collecting and keeping in print the stories and letters of H.P. Lovecraft for 30 years at the small press he co-founded, Arkham House, August Derleth also published the work of many other fantasy and horror greats while also maintaining a thriving writing career himself. He's one of fantasy literature's most indispensable figures for Arkham House alone.
Derleth also extrapolated a number of stories from notes, fragments, and sections of letters left by H.P. Lovecraft. This collection actually lists Lovecraft as the primary author (as Derleth himself would have), though there's little here that's actually written by Lovecraft. And I've actually read enough pastiches and homages derived from Lovecraft's Commonplace Book to recognize a couple of examples here.
The bad news is that Derleth's odd love of italics, especially for the concluding paragraph of a story in which terrible things are revealed, is displayed here. Boy, I hate that, and I'm not alone.
The good news is that while Derleth lacks Lovecraft's weird imagination, he can sometimes make up for this with a superior sense of how to depict rural settings and rural residents. Derleth, a regional Wisconsin writer when he wasn't Lovecraft's posthumous Boswell, has a fine eye for natural description. Even a slight story like the first one collected here, "Wentworth's Day", benefits from that studied and accurate creation of an isolated rural world.
Other than a story or two too many about Lovecraft's Innsmouthian hybrid human-amphibians, this is a solid collection. It's also weirdly soothing, which is not something I'd say about Lovecraft's work. The one real debit here is that Derleth's last work, which gives the collection its title, appears here unfinished as it was on Derleth's death in the early 1970's. Given Derleth's own work finishing up Lovecraft, surely someone could have paid Ramsey Campbell or Brian Lumley -- two discoveries of Derleth in the 1960's who are still popular and active writers today -- to complete the story. Preferably without concluding italics and exclamation marks. Recommended.