Neil Gaiman was asked to do a television series for the BBC. Lenny Henry helped, too. Unfortunately, they fiddled with it, and while the end result was good, it was not entirely true to Gaiman's vision. So he went home, and used his days off to write the story he wanted to tell.It was later adapted by Mike Carey and Glenn Fabry as a miniseries for Vertigo Comics. The series was explicitly based on Gaiman's novel, rather than the BBC's televised version. It was fairly well-received by critics, but fans took issue with the artwork's radically different depiction of several characters, particularly the Marquis de Carabas.A movie version has been in development hell for a while now.Lancaster University Theatre Group recently performed the first stage adaptation, adapted for stage by Peter Slaney.In March 2013, BBC Radio 4 aired a radio play version, adapted and directed by Dirk Maggs, and starring an astounding who's-who of British actors, led by James McAvoy as Richard and Natalie Dormer as Door. The radio play can be heard here.There is also now a short story in the same universe, How The Marquis Got His Coat Back.
Amazing Technicolor Population: For no real reason, the comics show Anaesthesia (an otherwise normal human, mind you) as being blue. An otherwise normal human who was born in London Above. In that same comic, the Marquis, described as having very dark skin, has solid, pitch black skin. Like Papa Lazarou.
Animal Stereotypes: Croup and Vandemar are described as giving very clear impressions of "a fox and a wolf". The Ratspeakers are sneaky and live in the sewers with the rats they serve. Lady Serpentine is, well, serpentine. Hunter is often compared to a lioness. The Marquis de Carabas is generally described in catlike terms, even being compared to a panther at one point. And, of course, his name comes from Puss in Boots. And he has more than one life, in a fashion.
Croup and Vandemar also never tire of telling people how many, and how painfully, they've killed.
Mr. Croup: We have assassinated a dozen kings, five popes, half a hundred heroes and two accredited gods. We are utterly professional. My point? My point is that we are assassins. We are cutthroats. We are not scarecrows.
Crystal Dragon Jesus: All the people of London Below swear by "Temple and Arch". It's never quite explained what this refers to, but it is thematically appropriate, given the deeper meanings of the other place names.
The House of Arch is Door's family, and "Temple" is left vague, but may be Temple Tube Station on the Embankment. It's not far from the Outer and Inner Temples which are the professional associations for barristers and judges in the City of London. Arch may be for Archway Tube Station or for Marble Arch.
Dark World: Right after Richard notices and saves Door and thus involves himself in the mess of Neverwhere, he suddenly finds that his ATM card no longer functions and people in his life act as if he was missing or never existed at all. And while a good deal of Neverwhere does take place underground, there are moments where it's clear that aboveground London has activity that's unseen by the average human being in the 'real world', especially on rooftops. Near the end, once Richard returns to the 'real world,' his ATM card is shown to function normally once more and those same people who forgot about him at the beginning recognize him and welcome him back from vacation.
Debt Detester: The Marquis de Carabas. He prefers it when people owe him things.
Evil Gloating: Invoked by the Marquis, who lets himself be (temporarily) killed because he has no doubt that someone like Croup would tell him their entire plan before killing him.
Exactly What It Says on the Tin: there really is a Knight's Bridge, there really is an Earl's Court, there really is an Angel Islington, etc. This is all a lot more potent if you know the station map, i.e., live in London.
Exact Words: In the comic, the Marquis gets Croup and Vandemar to give him an hour's Mercy Lead - except they only promise not to touch him for an hour. This doesn't mean they can't follow him, or tear a ladder off a wall while he's climbing it.
The Faceless: The Marquis de Carabas in the comics is an odd example: he has eyes and lips, but no other features, as the rest of his body is just a silhouette. He was described in the book as having extremely dark skin, and it is to be assumed the artist took it literally and gave him ink-black skin.
Although after he gets killed and brought back to life, the ink-black is streaked in places, revealing skin of a lighter shade underneath, so it may be some kind of costume or disguise.
False Innocence Trick: The Angel Islington seems to be a trusted ally to the heroes and informs them that he is tasked with protecting London Below due to his previous failure to adequately defend his previous city, Atlantis. They should have asked more detail about that before helping to free him. He destroyed Atlantis because he wasn't satisfied with their worship, and he's basically a Fallen Angel in the tradition of Satan with A God Am I pretensions, aiming to storm Heaven and declare himself God.
Fridge Logic: In-universe - Door wonders, in a dream, who put away her father's journal after he was killed, but forgets this by the time she wakes. The answer turns out to be significant.
Full Boar Action: The Beast of London. Other cities are stated to have had similar giant animals (a bear in Berlin, an alligator in New York). Note the "had" - they're mostly mentioned in the context of Hunter having killed them.
Gave Up Too Soon: Door agreed to meet up with the Marquis at the floating market. They could have touched him, had they known where he was. Dead. By the time he got better, they had already left.
...a man thrust what appeared to be a child's severed hand clutching a candle toward him as he passed, muttering, "Hand of Glory, sir? Send 'em up the wooden hill to Bedfordshire. Guaranteed to work." Richard hurried past, not wishing to find out what a Hand of Glory was, nor how it worked;...
Harbinger of Impending Doom: At the beginning, Door drops onto the sidewalk in front of Richard, out of nowhere and half-dead. His life abruptly gets a lot weirder.
Heart Is an Awesome Power: Opening things. To anywhere, whether there was a door there or not. And the first way we see Door use her power is to open up an assassin's chest.
Heroic Sacrifice: Hunter distracts the Beast in order to give Richard the opportunity to kill it. Although it's implied that she was essentially dying anyway before doing so, so this may be more of a Dying Moment of Awesome.
Also, the Marquis. He gets better.
Heterosexual Life-Partners: In a weird villain example, Croup and Vandemar. Richard isn't even particularly surprised at the end when Vandemar allows himself to be sucked into the vortex at the end because Croup has already fallen in.
It made some sort of sense, Richard thought: they were a team, after all.
Maybe Magic, Maybe Mundane: A few hints are laid down that all of Richard's experiences in London Below might really be a huge psychotic delusion, most especially the Ordeal, but this is not given special credence. The ending implies that it's real after all.
Meaningful Name: During the Victorian era, Henry Mayhew did an in-depth study of the darker side of "London Above". Also, the Marquis de Carabas is the fake title given by Puss in Boots to the miller's son he assists, although the character in Neverwhere has more in common with the cat than with his master, in both de Carabas' scheming and his multiple lives. The Marquis is stated to have picked his name deliberately. Realizing that the world runs on lies, he decided to become a lie, taking the name of a character whose life ran on a lie.
"Anaesthesia" is suspiciously similar to "Anastasia", especially considering that she disappears. But she might be coming back some time after the book is over.
Door's family, in line with their inherited ability as "Openers", all have names that suggest a door or entrance: her mother and father the Lord Portico and Lady Portia, her sister Ingress, her brother Arch.
Lamia is named after Greek Demons which have a lot in common with vampires.
All of the Black Friars have names related to the color black, shadows, or darkness.
Hunter seems to have this sort of reputation in-universe - at one point the characters are each being made fun of in turn by a jester as they introduce themselves. When Hunter professes her name, everybody gets really quiet.
Also, Serpentine. The moment Door realizes they're in her house, she goes nuts.
Odd Couple: Mr. Croup and Mr. Vandemar are pretty much opposites, apart from their fashion sense, powers, and love of killing things.
Oh Crap: The first indication we get that freeing Islington is not a good idea. After the trio leave the Black Friars upon winning the ordeal and the MacGuffin: 'We have lost the key. God help us, we have lost the key.'
The Only One I Trust: Old Bailey would appear to be this for the Marquis. The Marquis quite literally trusts him with his life, and rather touchingly when you consider he'd probably be better off if he didn't, Old Bailey earns it.
Although it should be pointed out that the Marquis trusts Old Bailey not for any reason of comradeship or sentimentality, but because Old Bailey has no choice but to return the Marquis's favour. "I was a fool..."
Our Vampires Are Different: They're called Velvets, they dress like elegant Gothic aristocrats, are apparently all women, and suck the heat out of the body of whoever's dumb enough to kiss them. The Velvets actually have a good bit in common with the Japanese folk monster yuki-onna (snow woman), down to the freezing kiss.
Perception Filter: Normal people are unable to notice those from London Below except in very extreme cases.
Pluralses: Old Bailey asks for "shoeses and gloveses"
Reality Subtext: It is unknown if this was intentional, but the bits of the book that take part in Angel tube station can have this impact due to Angel being home to Slimelight, a long running alternative nightclub. It is not uncommon for ordinary commuters to be accompanied by club patrons with some interesting ideas about fashion.
Red Pill, Blue Pill: Richard spends most of the story striving to find the way to get back to his old life. When he does, he regrets it.
Red Baron: Richard gains the nickname The Warrior after killing the Beast. It's implied that Hunter's moniker may be an example of this, as well.
Red Herring: The end of one chapter makes it look like the Marquis will be revealed as Croup and Vandemar's employer.
Room 101: The room the Black Friars put Richard in for "the ordeal."
Rule of Three: Getting the key from the Black Friars requires passing three tests - and coincidentally, there are just three people in Door's party by then. Also the requirements for Islington to be freed from its prison; as Islington describes it, "A key. A door. An opener of the door. There must be the three, you see: a particularly refined sort of joke."
She was dressed in a variety of clothes thrown over each other: odd clothes, dirty velvets, muddy lace, rips and holes through which other layers and styles could be seen. She looked, Richard thought, as if she'd done a midnight raid on the History of Fashion section of the Victoria and Albert museum, and was still wearing everything she'd taken.
Somewhat averted in the comic; Door's clothing is still somewhat hodgepodge, but it's at least in some sort of noble style.
Scenery Porn/Scenery Gorn: The TV adaptation uses London's hidden and grimy underside practically as an extra character, and has some spectacular shots of the Royal Mail tunnels, the Greathead Shield, Down Street Station, St. Pancras/Midland Grand Hotel and Bazalgette's sewers.
Mr. Croup: It is saddening to reflect that there are folk walking the streets above who will never know the beauty of these sewers, Mister Vandemar.
Senseless Sacrifice: The Marquis allows himself to be tortured to death (temporarily) by Croup and Vandemar, so that they will let slip info on their employer and purpose, but by the time he gets back to the rest of the characters, that particular cat is already out of the bag.
Tons to Alice's Adventures in Wonderland and Through the Looking-Glass. Notable instances include Richard noting that he is believing many impossible things and he hasn't even had breakfast yet (the White Queen tells Alice, "Why, sometimes I've believed as many as six impossible things before breakfast") and sarcastically asking "Jam tomorrow?" to convince Messrs. Croup and Vandemar that Islington is never actually going to pay them (a reference to the same White Queen telling Alice, "The rule is, jam to-morrow and jam yesterday – but never jam to-day").
Richard says "Lead on, Macduff", a common misquotation from Macbeth, at the end of chapter eleven. After he leaves, Brother Fulginous notes that it's actually "Lay on, Macduff", but he "hadn't the heart to correct him. He sounded like such a nice man."
Stripperific: In Neil Gaiman's audio commentary on the DVD release of the miniseries, one of his complaints is that Hunter was meant to be stripperific and she didn't turn out that way due to the aforementioned Executive Meddling.
Thanatos Gambit: The Marquis arranges his own death at the hands of Croup and Vandemar, in order to profit from the inevitable Evil Gloating. He had also arranged to return from the dead afterward.
Theme Naming: Door's family are all named after entrances to buildings (Ingress, Arch, Lord Portico and Lady Portia), the Black Friars are named after synonyms for black, and most of the other characters (including the Black Friars' order itself) are named after buildings or neighbourhoods in London - or rather, buildings or neighborhoods in London have been named after most of the other characters.
Time Abyss: The Labyrinth of the Beast of London is said to have lain there under the site on the Thames before the legendary King Lud himself founded the first village. It was built to keep a Sealed Evil in a Can. Though the Beast only arrived in the 17th century.
Older still are Islington and Croup and Vandemar, although in the latter's case this might be due to their possible ability to move through time.
Wacky Wayside Tribe: London Below is apparently inhabited totally by these; the ones who fish through the sewers and have the smell to match, the various bodyguards, the "Shepherds of Shepherd's Bush", the Renfair nuts who live on the Earl's Court train...
Meanwhile, Door herself apparently is the sole survivor of the massacre of her family because she ran into a Wacky Wayside Tribe of timelost Roman legionnaires. In fact, the clannishness and disparity of the different cultures of London Below was a pressing concern of Door's late father — he wanted to find a way to unite the people so they would stop warring.
Wicked Cultured: Mr. Croup's efforts to acquire an exquisite porcelain statuette look like this at first. And then he eats it with terrifying glee. He simply loves to destroy precious and beautiful things.
Word of Gay: Or rather, word of Gaiman. Gaiman has stated that there are two gay characters among the principal cast, but has not elaborated further. Hunter is generally considered to be one of them. Hunter's dream is about her hunting a giant weasel to give the pelt to a girl who had caught her eye, and the girl is mentioned as having been "appropriately grateful". This is stated to have actually happened - it's only the particulars of the dream that differ. She also has subtext with Serpentine. The other one is harder to tell, but given process of elimination, presumably the Marquis.