Newman's first two books were both non-fiction. Ghastly Beyond Belief: The Science Fiction and Fantasy Book of Quotations (1985), co-written with his friend Neil Gaiman, is a light-hearted tribute to entertainingly bad prose in fantastic fiction. Nightmare Movies: A critical history of the horror film, 1968-88 (1988) is a serious history of horror films.

Nightmare Movies was followed by Wild West Movies: Or How the West Was Found, Won, Lost, Lied About, Filmed and Forgotten (1990) and Millennium Movies: End of the World Cinema (1999). Newman's non-fiction also includes the BFI Companion to Horror (1996) and Horror: 100 Best Books (co-editor, 1988), which won a Bram Stoker Award for Best Non-Fiction.

Newman acts as one of several contributing editors to the UK film magazine Empire, as well as writing the monthly segment, "Kim Newman's Video Dungeon" in which he gives often scathing reviews of recently released straight-to-video horror films. He also contributes to Rotten Tomatoes, Venue and Sight & Sound.

A recurring feature of Newman's fiction is his fondness for reinterpreting historical figures (particularly from the entertainment industry) and other authors' characters in new settings, either realistic alternate-history or outright fantasy. Some of these characters (e.g. Dracula) are easily recognised. Many more, particularly minor characters, are deliberately obscured and may be considered Easter eggs for perceptive readers. An example is the appearance of the American John Reid who just so happened to own a silver mine and who exported silver bullets to Great Britain in Anno Dracula (a nod to the Lone Ranger). Or the appearance of an American actor named Kent who would be cast as "Hercules" in an Italian production of the same name (apparently a nod to both George Reeves and Steve Reeves [no relation] who played Superman and Hercules, respectively. (In the novel Dracula Cha Cha Cha aka Judgment of Tears: Anno Dracula 1959.)

Novels

Newman's first published novel was The Night Mayor (1989), set in a virtual reality based on old black-and-white detective movies. In the same year, as "Jack Yeovil", he began contributing to a series of novels published by Games Workshop, set in the world of their Warhammer and Dark Future wargaming and role-playing games. Games Workshop's fiction imprint Black Flame returned the Dark Future books to print in 2006, publishing Demon Download, Krokodil Tears and an expanded, 250-page version of the short story "Route 666". There are no plans for Newman to finish the series.

A famous novel is Anno Dracula (1992). The novel is set in 1888, during Jack the Ripper's killing spree...but a different 1888 to the one we know, in which Dracula became the ruler of England. In the novel, fictional characters...not only from Dracula, but also from other works of Victorian era fiction...appear alongside historical persons. One major character, the vampire Geneviève Dieudonné, had previously appeared (in a different setting) in his Warhammer novels. (Newman has stated there are three alternate versions of Geneviève: the Warhammer version, the Anno Dracula version, and a Diogenes Club version who appears in the Seven Stars collection of linked stories and The Secret Files of the Diogenes Club.)

Anno Dracula was followed by a series of novels and shorter works that followed the same alternative history, including The Bloody Red Baron (set in World War I), and Dracula Cha Cha Cha (titled Judgment of Tears: Anno Dracula 1959 in the US). Some of the short stories are available online; see below.

Other novels include Life's Lottery (1999), in which the protagonist's life story is determined by the reader's choices (an adult version of the Choose Your Own Adventure series of children's books), The Quorum (1994), Jago (1991), and Bad Dreams (1990).

He wrote a Doctor Who novella, Time and Relative, published by Telos in 2001.

Short stories

Newman is a prolific writer of short stories; his first published story was "Dreamers", which appeared in Interzone in 1982. His short story collections include The Original Dr. Shade, and Other Stories (1994), Famous Monsters (1995), Seven Stars (2000), Where the Bodies are Buried (2000), Unforgivable Stories (2000), The Man from the Diogenes Club (2006) and The Secret Files of the Diogenes Club (2007). There is also Back in the USSA (1997), a collection of stories co-written with Eugene Byrne, set in an alternate history where the United States had a communist revolution in the early twentieth century and Russia did not.

Many of his stories...notably those collected in Seven Stars, The Man from the Diogenes Club and The Secret Files of the Diogenes Club...feature agents of the Diogenes Club, the gentlemen's club created by Arthur Conan Doyle for the Sherlock Holmes story "The Adventure of the Greek Interpreter". In Newman's stories, it is a cover for a top-secret establishment of the British government, described as "an institution that quietly existed to cope with matters beyond the purview of regular police and intelligence services".

One sequence focuses on the adventures during the 1970s of psychic investigator Richard Jeperson; the stories homage various aspects of '70s British culture through adventures reminiscent of '70s television series such as The Avengers and Department S. (A version of the Diogenes Club also appears in the Anno Dracula series, complete with alternative version of Jeperson. The Diogenes Club series, conversely, sometimes includes alternative versions of characters who first appeared in the Anno Dracula series.)

The short story "Famous Monsters", in which a Martian left over from the invasion in H.G. Wells' The War of the Worlds gets a job in Hollywood, was included on an information package sent to Mars by a US-Russian probe in 1994.

• The Night Mayor (1989)
• Bad Dreams (1990)
• Jago (1991)
• The Quorum (1994)
• Back in the USSA (1997) (with Eugene Byrne)
• Life's Lottery (1999)

• Anno Dracula series
• Anno Dracula (1992)
• The Bloody Red Baron (1995)
• Dracula Cha Cha Cha (also published as Judgment of Tears) (1998)
• Johnny Alucard (planned)

• Time and Relative (2001)

As "Jack Yeovil"

• Warhammer setting
• Drachenfels
• Beasts in Velvet
• Genevieve Undead (three novellas published as a single book)
• Silver Nails (short stories)
• The Vampire Genevieve (compilation of the above four books)
• Dark Future setting
• Krokodil Tears
• Demon Download
• Route 666
• Comeback Tour
• Orgy of the Blood Parasites

• The Horror Writers of America's Bram Stoker Award for Best Non Fiction (Horror: 100 Best Books)
• The British Science Fiction Award for Best Short Fiction (The Original Dr Shade)
• The Dracula Society's Children of the Night Award for Best Novel (Anno Dracula)
• The Fiction Award of the Lord Ruthven Assembly (Anno Dracula)
• The International Horror Critics' Guild Award for Best Novel (Anno Dracula)
• The International Horror Critics' Guild Award for Best Novella (Coppola's Dracula)
• Prix Ozone for Best Novel (Anno Dracula)
• The British Fantasy Award for Best Collection 2000 (Where the Bodies Are Buried)

Kim Newman has been nominated for the Rondo Hatton Classic Horror Award six times and for the World Fantasy Award seven times.