H.P. Lovecraft is an American horror writer whose stories deal with an Ancient shadowy conspiracy by Alien beings to conquer the Earth. His fictional stories influenced much of growth of late 20th century paranoia that gave rise to conspiracies and conspiracy theory.
Cthulhu and the Necronomicon Edit
His most famous creation is the Elder Being known as Cthulhu. His existence predates mankind; and this evil alien being has been on Earth for eons - but trapped by forgotten magics into lying dormant in a deathlike state in the ruins of his city R'yleh which lies sunken at unknown depths in the Pacific Ocean. Cthulhu is indescribably evil and alien to mankind - and is worshipped by certain unsavory and degenerate races as a god. Cthulhu can influence your dreams - and more than a few tales circulate of the visions of nervous scholars who speak of reading a page of the dread Necronomicon - and speaking with strange non-human entites from Beyond ... and who go mad from the secrets revealed to them by this vile book.
The Cthulhu Mythos has grown considerably with the numerous contributions of other writers. By the mid-70's at least one author (Berglund) had published a comprehensive bibliography, now rare, of Cthulhu stories by authors other than Lovecraft.
To sample the Lovecraft literature at its best is to read his short novel "At The Mountains of Madness". Aside from numerous popular paperback editions, a small press publisher, Arkham House, published his collected works in five volumes as well as numerous volumes of his letters. Other notable short stories are "The Rats in the Walls" and "Pickman's Models".
Lovecraft's essay "Supernatural Horror in Literature" is well worth reading.