Along the shore the cloud waves break,
The twin suns sink beneath the lake,
The shadows lengthen
Strange is the night where black stars rise,
And strange moons circle through the skies
But stranger still is
Songs that the Hyades shall sing,
Where flap the tatters of the King,
Must die unheard in
Song of my soul, my voice is dead;
Die thou, unsung, as tears unshed
Shall dry and die in
— Cassilda's Song in "The King in Yellow", Act I, Scene 2
Carcosa is a fictional city first mentioned in the Ambrose Bierce short story An Inhabitant of Carcosa (1891). In Bierce's story, the ancient and mysterious city is barely described, and is viewed only in hindsight (after its destruction) by a character who once lived there. The city was later used more extensively in Robert W. Chambers' book The King In Yellow. Chambers had read Bierce's work and borrowed other names as well, including Hali and Hastur.
In Chambers' book, and within the apocryphal play mentioned several times in that book, the city is a mysterious, ancient, and possibly cursed place. The most precise description of its location given is that it said to be located on the shores of Lake Hali in the Hyades star cluster. The descriptions given of it thus make it clear that it must be located on another planet, or possibly even in another universe.
The name may have originally been derived from the medieval city of Carcassonne in France.
Later writers, including H. P. Lovecraft and his many admirers, became great fans of Chambers' work and incorporated the name of Carcosa into their own stories, set in the Cthulhu Mythos. In the stories of August Derleth and a few others Carcosa is the residence of the Great Old One Hastur. Occasionally, Hastur will alter reality and merge parts of Earth into Carcosa, usually bringing along unwilling people as well.
In the short story More Light, in which James Blish presented his version of a complete text of the play ''The King in Yellow'', Carcosa was described as having four singularities: that it appeared overnight, that no one could tell whether it sat upon the waters of Lake Hali or beyond them on the unseen farther shore, that the rising moon appeared to be in front of the city's towers rather than behind them, and that one knew the city's name to be Carcosa the moment one looked upon it. In Blish's version, Carcosa was created as a city of exile for the King in Yellow, because he was not king in Aldebaran.
Marion Zimmer Bradley also used the name Carcosa for a city on her fictional planet ''Darkover''. According to her, this usage and the appearance of other distinctive names from Chambers' work dated from her own youthful fascination with "The King in Yellow" and her ambitions to produce her own reconstruction of the play on the basis of the fragments in Chambers' works. Only later did she transform those early fantasy writings into science fiction by relocating them from a parallel earth to a distant world under a red sun.
Carcosa Press was a specialty publishing firm formed by David Drake, Karl Edward Wagner, and Jim Groce who were concerned that Arkham House would cease publication after the death of its founder, August Derleth. Carcosa put out two notable collections of pulp horror stories, Manly Wade Wellman's Worse Things Waiting (1975) and Hugh B. Cave's Murgunstrumm and Others (1978), both edited by Wagner and illustrated by Lee Brown Coye.
The Carcosa Press colophon depicts the silhouette of a towered city in front of three moons.