Viriconium is a fictional city created by M. John Harrison and also the name of the cycle of novels and stories set in and around it.
Viriconium is on a future Earth littered with the technological detritus of millennia (partly inspired by Jack Vance's Dying Earth series and Mervyn Peake's Gormenghast series  although the works are also influenced in their imagery by the poems of T.S. Eliot).
The Pastel City concerns the defence of the eponymous city against northern "barbarians" by a melancholy swordsman and poet, 'sometime soldier and sophisticate' Lord tegeus-Cromis. tegeus-Cromis is the hero of the Methven but believes he has finished soldiering forever - until the mercenary Birkin Griff brings dire news of the war between the two queens and the hazard facing the Pastel City. They must travel to the Great Brown Waste to find Tomb the Dwarf, and join forces to fight for Queen Jane and Viriconium - for Canna Moidart and the Wolves of the North have awoken the geteit chemosit, alien automata from an ancient science, which will destroy everything in their path.
The second novel of the series, A Storm of Wings, is set 80 years after the events described in The Pastel City. Lord tegeus-Cromis had broken the yoke of Canna Moidart. But now the Reborn Men, awoken from their long sleep, have inherited the Evening Cultures. Their first representative is Alsath Fulthor. In the wastelands to the north and west of Viriconium, a city is being built - but not by men. It is the Time of the Locust. The attackers are insect-like aliens who threaten to turn the inhabitants of the Pastel City into hideous, mindless insects: the story is told through both human and alien points of view and perceptions. The main characters are a resurrected man, an assassin, a magician, a madwoman, and Tomb, the Iron Dwarf. 
The third novel of the series, In Viriconium, whose working title was By Gas Mask and Fire Hydrant, parodies Arthurian motifs and deconstructs the whole series to show that Viriconium is just a fiction: the protagonist Audsley King realizes this and at last can paint the real world, which is our own. The novel is divided into sections named after cards of an imaginary Tarot. The story concerns the efforts of one artist, Ashlyme, to rescue another - the frail, consumptive, dying Audsley King - from the plague zone (the latter is a motif that recurs in Harrison's novel Nova Swing). It is a desperate, misconceived enterprise which draw Ashlyme into unwilling alliance with the sinister dwarf The Grand Cairo, and which goes bizarrely wrong. Yet out of the shambles comes the clue to lifting the plague which symbolises a paralysis of will. Resonances in the text include the art of Aubrey Beardsley, post-Impressionist art, Mervyn Peake and Wyndham Lewis.
The short fiction of the Viriconium sequence replays this attrition; finally, in "A Young Man's Journey to Viriconium" (later retitled "A Young Man's Journey to London"), Viriconium has become little more than a dream.
Variations of the city appear throughout the series (most frequently as Uriconium and Vriko), in an attempt by Harrison to subvert the concept of thoroughly-mapped secondary worlds featured in certain works of fantasy, particularly those by J. R. R. Tolkien and his host of successors.
- The Pastel City (novel, 1971)
- A Storm of Wings (novel, 1980). Various editions have different dedicatees. The US first edition (Doubleday, 1980) is dedicated to Harlan Ellison. The Sphere 1980 edition is dedicated to various staff of Savoy Books including Michael Butterworth, John Mottershead and David Britton. The Unwin 1987 printing is dedicated to Christopher Fowler.
- In Viriconium (novel, 1982). The novel was nominated for the Guardian Fiction Prize in 1982. The US edition, retitled The Floating Gods (Timescape, Feb 1983) is dedicated to Fritz Leiber (the UK edition had been dedicated to two of Harrison's friends). The US edition also has a three paragraph 'Author's Note' regarding Viriconium which did not appear in the UK editions.
- Viriconium Nights (short stories, 1985), consisting of the following stories in this order:
- "The Luck In the Head". This story was adapted as a graphic novel by illustrator Ian Miller and published by VG Graphics in 1991 (distributed in the US by Dark Horse Comics).
- "The Lamia & Lord Cromis"
- "Strange Great Sins"
- "Viriconium Knights"
- "The Dancer From the Dance"
- "Lords of Misrule"
- "A Young Man's Journey To Viriconium"
A 1988 omnibus entitled Viriconium (Viriconium (1988 collection)) omits the first two novels; it consists of the third novel, In Viriconium, and the full contents of the short story collection Viriconium Nights. The stories in this omnibus are in the same running order as in the 1985 first edition. The omnibus has an introduction by Iain Banks.
All four works of the sequence were published in the U.K in a single omnibus volume called Viriconium in 2000. (Viriconium (2000 collection)). The stories are arranged in a different sequence (presumably chronological) which see the Viriconium Nights stories in a different running order than in the 1985 first edition and the 1988 omnibus. An American edition of all four was published in 2005, with an introduction by Neil Gaiman. The novels are sequenced in publication order, but the short stories are in a different sequence. This edition was published in audio in late 2011 by Neil Gaiman Presents, read by Simon Vance.
- "A Storm of Wings" in David Pringle, Modern Fantasy: The 100 Best Novels, Grafton Books, 1988 ISBN 0-246-13214-0 (pp. 201-203).
- "What It Might Be Like To Live In Viriconium," by M. John Harrison
- "On Viriconium: some Notes Toward an Introduction." by Neil Gaiman