The House of R'lyeh contains five scenarios that closely follow the events of H.P. Lovecraft stories. They are set in Boston, Providence, the British Isles, continental Europe and the Middle East. None of the scenarios need to be played at set dates or in a set order, but they could be run in the order presented to form a loose campaign using optional links between scenarios to draw investigators from one to the other.Alternatively, the scenarios may be used to supplement classic Call of Cthulhu campaigns such as The Shadows of Yog-Sothoth and The Fungi from Yuggoth, the latter currently in print as The Day of the Beast, both of which suggest their component scenarios should be interspersed with others. The first scenario in this book, The Art of Madness (Brian Courtemanche) follows on from the events of the Lovecraft tale Pickman's Model. Artist of the macabre, Richard Upton Pickman, is now a ghoul living a subterranean netherworld beneath Boston creating a new school of art. There are several ways that player characters might be drawn into investigating his macabre activities and, while dangerous, Pickman's intent is not particularly lethal. The difficulty for investigators will be to resolve the situation without becoming compromised. While in New England, the investigators discover The Crystal of Chaos (Peter Gilham with David Conyers), a retelling of the events of Lovecraft's The Haunter of the Dark. Hired by professors of Miskatonic University, the investigator seek out a fabled crystal with origins in Ancient Egypt, but they soon find a far greater evil lurks in an abandoned church in Providence. This scenario originally appeared in Different Worlds issue 34, May/June 1984, and has been expanded and revised in this publication. The Return of the Hound (Glyn White) draws investigators to an auction in Yorkshire, in England, where a rare edition of the Necronomicon is going to be sold. The previous owners, the decadent occultists from Lovecraft's The Hound, are dead, as that tale recounts, but what they unearthed in 'a Holland churchyard' has grown strong, and has schemes of its own to fulfill. The amount of danger the investigators face is dependent on how determined they are not to let this Necronomicon fall into the wrong hands. The Jermyn Horror (David Conyers) takes place in Britain, beginning in London and then moving to Huntingdon with the investigators seeking a rare edition of Regnum Congo, reputedly to be found in the crumbling estate of the deceased Jermyn family as described in Lovecraft's Arthur Jermyn. The search is imperiled by a creature that a Jermyn brought back from the Congo some three hundred years ago that haunts the mansion seeking a human vessel for its escape. Nameless City, Nameless Terrors (Brian M. Sammons) concludes this collection with an expedition into the heart of Arabia's Empty Quarter in search of Irem as described in Lovecraft's The Nameless City. This scenario requires investigators to risk their bodies and their minds as, in the midst of the desolate ruins of Irem, the investigators learn something of the nature of the Great Old Ones, and perhaps forestall the rising of Cthulhu from his watery grave.