->''It was a dark, blustery afternoon in spring, and the city of London was chasing a small mining town across the dried-out bed of the old North Sea.''
-->--Opening sentence of ''Mortal Engines''. [[spoiler:[[BookEnds Closing sentence of the entire series]].]]

The Mortal Engines Quartet is an award-winning, critically acclaimed series of novels by the English author Philip Reeve, marketed (somewhat ridiculously) as ''The Hungry City Chronicles'' in America.[[note]]possibly because of the Creator/StanislawLem anthlogy that was released as ''Mortal Engines'' in the US[[/note]] Four books were written in chronological order: ''Mortal Engines'' (2001), ''Predator's Gold'' (2003), ''Infernal Devices'' (2005), and ''A Darkling Plain'' (2006). Prequel books set many centuries before the first book are currently being published. ''Fever Crumb'' (2009), ''A Web of Air'' (2010) and ''Scrivener's Moon'' (2011) are out so far, with more to come.

Mortal Engines takes place in a post-post-post-post-post-apocalyptic UsedFuture. Nations no longer exist, except in the lands of the Anti-Traction League. Traction Cities - entire cities mounted on caterpillar tracks for mobility - are fiercely independent city-states, using giant jaws to devour one another for resources in a horribly unsustainable city-eat-city environment known as Municipal Darwinism: large cities eat small cities, small cities eat towns, towns eat suburbs, and everyone eats non-moving or "static" settlements. Trade is mostly accomplished by airship, though sometimes cities of roughly equal size (unable to devour each other) will stop to trade. Much of the AppliedPhlebotinum involves Old-Tech, ancient remains of lost civilisations ranging from statues of MickeyMouse ("animal-headed gods of lost America") to {{Forgotten Superweapon}}s.

Traction Cities' military and ideological counterpart, the Anti-Traction League, is a vast Eastern coalition of static settlements, who aim to remove the abomination of Traction Cities from the world.

Something worth mentioning, given the amount of back-and-forth editing in the page history, is that the most prominent Stalker is named Shrike in most editions and Grike in the North American ones. For ThemeNaming reasons made clear in ''Fever Crumb'' - that is, all the Stalkers in his 'batch' were named after birds - 'Shrike' (a small predatory bird) makes considerably more sense than 'Grike' (a feature of limestone pavements).

Creator/PeterJackson and WETA Digital are currently working on a film adaptation of the first book, Mortal Engines, though the release date remains uncertain.

----
!!This book series provides examples of :

* ActionGirl: Hester Shaw. Later a DarkActionGirl.
** Also, Anna Fang in the first book. With an equally unclear distinction between ActionGirl and DarkActionGirl.
* {{Adorkable}}: Hester sure thinks Tom is.
* AdventurerArchaeologist: Played straight with Thaddeus Valentine, subverted by Nimrod Pennyroyal.
* AerialCanyonChase: In Predator's Gold, Tom flies an airship at street level through a moving city to lose the pursuit. One of the airships chasing him does crash.
* AerithAndBob: Let's see. There's Freya... Shrike... Gargle... Smew... Fishcake... brothers Lego and Duplo... Oenone Zero... Nabisco Shkin...''Tom''...
** A lot of names in the series, given the distant-future nature, are well-known brands or companies to us, but whose meaning has been lost. Notably, names like Windolene and Napster. Also, Reeve admits to naming a handful of the characters in Mortal Engines after towns and locations around his home, hence names like Chudleigh and Miss Plym. Furthermore, the Lost Boys almost exclusively get named phenomena related to aquatic life, water, or fish, like Gargle, Remora and Fishcake. And yes, there are more 'normal' names like Hester, Tom, Thaddeus, Katherine and Anna.
* AfterTheEnd: The Apocalypse is here known as the Sixty Minute War, and was by all accounts an hour to remember: the North American continent gets glassed, Central America is completely wiped off the map, geological instability causes new chains of volcanoes to spring up all over the place, and humanity is thrown into centuries of anarchy and barbarism.
* AirborneAircraftCarrier: Airhaven is an entire floating town, complete with docking for more conventional airships, so it counts.
** More conventionally, several of the larger military airships probably count.
* AllHailTheGreatGodMickey: Literally -- the first book has Tom running past statues of "...Mickey and Pluto, the animal-headed gods of lost America."
* AntiVillain: [[spoiler: Valentine turns out to be a [[SlidingScaleOfAntiVillains Type II]].]]
* AnyoneCanDie: And HOW. See KilledOffForReal below.
* ApocalypseHow: Though humanity's back on its feet (15,000 or so years will do that for a civilization) the Sixty Minute War had such massive environmental effects and dumped so many nukes that south China was flooded, Antarctica de-frosted, seas moved around, pretty much everything north of New York City froze solid, Australia seems to have vanished (though WordOfGod says he just never got around to writing anything about it) and ''Panama ceased to exist.'' Not flooded, '' severed and destroyed.'' Class 2, verging on a class 3a.
** [[spoiler:The Stalker Fang]] [[DeathFromAbove attempts a Class 3a]] in ''A Darkling Plain''.
* ApocalypseNot: Hits ''hard'' in the third and fourth books as more and more cities are depicted and the lands of the Anti-Tractionists are revealed to cover swaths of Asia and Africa, sort of turned back on itself as the previously unmentioned wider human civilisations are in the process of annihilating each other in a stalemate war.
* AppliedPhlebotinum: Old-Tech can be jewellery, can be useless but shiny rubbish, can be city-melting superweapons, and can make cities fly. Almost nobody can tell the difference.
* {{And I Must Scream}}: Aspects of this in stalker technology. Individuals do not find rest in death, i.e. [[spoiler: Anna Fang / Kit Solent]], but instead are nightmarishly brought back to life through creepy old-tech (there are some gruesome descriptions of how this happens). What makes it eligible for this trope is [[spoiler: they often remember who they were, and quite possibly are unable to destroy themselves for various reasons - such as due to tinkering done to their brains. They must endure as half-preserved, monstrous killing-machines. ]]
* ArtisticLicenseEconomics: Municipal Darwinism doesn't really make much sense: You move a literally ''city-sized'' mass of people, buildings, and machinery around on wheels, burning [[OhMyGods gods know]] how much fuel per second, dealing with what must be ''staggering'' maintenance costs and trying to absorb unimaginable initial investments... All so you can steal some pitiful resources from smaller, ''less successful'' cities trying to do the same thing (a labour-intensive process that involves tearing apart lots of valuable infrastructure in the target city).
** DiscussedTrope: In the first book, one character explicitly says that Municipal Darwinism is stupid -- it arose at an earlier time, when constant disasters and cataclysms forced communities to be mobile, and continues on, despite making no sense, just because people are set in their ways. The Anti-Traction League certainly thinks that it makes for bad economics.
* ArtisticLicenseEngineering: The books [[AcceptableBreaksFromReality probably could not exist without this]]. The premise of entire ''cities'' that roll around on giant wheels and tracks, reaching speeds of a hundred kilometres per hour or more, using technology for the most part ''inferior'' to what exists in RealLife today, poses quite a few engineering challenges. (What structural material is light, strong, and easy enough to mass-produce to allow this? How are the engines powerful enough? How do they get -- or even ''store'' -- enough fuel to run these engines continuously for days or weeks at a time? How is the weight of an entire ''city'' distributed amongst the wheels?) Of course, the answer is that the cities run on RuleOfCool -- and they're certainly cool enough to make it all worth it.
** There are other, smaller examples. In one scene in ''Predator's Gold'', for example, a character rides around on a tiny personal airship the size of a couch, kept aloft by a tiny gas-bag. It's small enough to be suitable for indoor flight. In RealLife, even the smallest lighter-than-air craft still need comparatively ''huge'' gas bags to work -- compare [[http://www.youtube.com/watch?v=a9jVS2AqD2I this video of a tiny Real Life airship]]. (Airships actually get more efficient when it comes to lifting power as they get larger, which is why RealLife zeppelins were so massive).
* BadassLongCoat: Anna Fang.
** Also Tom, as can be seen on the second book cover.
*** And, to a lesser extent, the London Engineers and their white rubber lab coats.
* BeautyIsNeverTarnished: Deliberately and avoided by Hester Shaw, who is horribly scarred and disfigured. As in missing an eye, most of her nose, and a good chunk of her mouth.
* BaseOnWheels: Base? Pff. ''City'' on wheels. Really BIG cities on wheels.
** On a much smaller scale, ''A Web Of Air'' features funicular houses, which only move up and down on rails.
* BettyAndVeronica: Although they don't meet until the very end of the book, Katherine Valentine and Hester Shaw can be seen as this. The second book plays the trope straight with Freya Rasmussen and Hester Shaw.
* BewareTheNiceOnes: Although Bevis Pod is genuinely nice, Katherine is still shocked to see [[spoiler:how calmly he can kill]].
* {{BFG}}: Hester gets a huge armour-piercing jezail in ''A Darkling Plain'', which also features lightning guns and ''anti-city artillery''.
** And MEDUSA ([[spoiler: a giant laser weapon]]) and ODIN ([[spoiler: a {{KillSat}}]]).
* BilingualBonus: Lots of these in German, French and Chinese, in particular some of the city names.
* BittersweetEnding: [[spoiler: The Traction War cost untold numbers of lives, Tom and Hester are dead and Shrike is left bereft...but New London heralds the rise of a type of moving city that will no longer damage the world, Wren and Theo go on to make new lives for themselves, and Shrike, after hibernating for hundreds of years, wakes up to find the world green again and settles into his new role - and family - as a remembering machine.]]
* BiTheWay: [[spoiler: Fever Crumb and Auric Godshawk.]]
* BlackBox
* BrokenBird: Hester, so much.
* BookDumb: Hester, especially compared to [[BookWorm Tom]].
* BookEnds: The first line of the first book [[spoiler:becomes Shrike retelling the story hundreds of years later at the end of the fourth book]].
* BrickJoke: At the end of the first book, Tom insists (not convinced himself) that ''someone'' must have survived [[spoiler:the destruction of London]]. About halfway through the fourth, [[spoiler:it turns out he was right.]]
** A small, but funny example is Wren's stylish haircut, first briefly mentioned at the start of ''A Darkling Plain'', and then forgotten until a blink-and-you'll-miss-it moment halfway through the book...
* BrokenAce[=/=]BrokenPedestal: Thaddeus Valentine isn't as nice as he seems...
* ChekhovsGun: The seedy in ''Mortal Engines'', which Tom finds at the very beginning of the book and later uses as a payment to be accepted aboard a town.
** Early in the same book, Katherine mentions that her father's copilot during his expedition to America was a woman, [[spoiler:which enables her to figure out the link between her father, Pandora Rae, and Hester Shaw much later]].
** The Tin Book of Anchorage in ''Infernal Devices''.
** In ''A Darkling Plain'', Wolf Kobold pays Tom and Wren so they fly him to London. At the very end of the book, Wren remembers the money and uses it to buy her own airship.
* CombatPragmatist: Hester uses basically anything she can find as a weapon, including crossbows, [=BFGs=], knives, swords and a typewriter(!).
* ColonyDrop: Slow Bombs are remote-controlled asteroids.
* CoolAirship: The ''Jenny Haniver''. It's built of junk, but hey, so's the ''Millennium Falcon''. A connection noted by Tom's "It's made of junk!" comment upon first seeing the Jenny.
* CourtMage: Nintendo Tharp. He has [[FutureImperfect powerful apps]].
* CrazyPrepared: [[spoiler:Cynthia Twite. Not only did she have a time bomb under the ship should her assassination fail (And it did), but she also already forged the suicide note for that guy she killed using her poison-tipped hairpin which she had for such an occasion.]]
* CrazySurvivalist: On an enormous scale.
* DeadGuyOnDisplay: A classical Type 2 in ''Fever Crumb'', where the flayed skins of London's former Scriven masters are put on display following the Skinners' Riots.
* {{Determinator}}. Any Stalker, but Shrike in the extreme. A lot of the human characters too, particularly the frail Oenone Zero, also have an unexpected, somewhat terrifying determination to them.
* DistantFinale
* ADogNamedDog: Despite actually being a wolf.
* DrivenToSuicide: [[spoiler:Hester stabs herself in the heart rather than live without Tom.]]
* [[DroppedABridgeOnHim Dropped An Airship On Him]] [[spoiler:Bevis]].
** Also, Shrike. Though it's more [[spoiler: ran a city over him.]]
*** [[spoiler: He [[ImplacableMan got better though.]] Twice.]]
* {{Eagleland}}: Type II in the backstory. One historian notes that "the old American Empire was quite mad towards the end," coming up with crazy EnergyWeapons that drew power from places outside the physical universe. [[spoiler: One of them, MEDUSA, is central to the plot of the first novel.]]
* EarlyBirdCameo: After a fashion. An aviatrix named Cruwys Morchard is mentioned in passing early in the second book; she's a significant player in the fourth [[spoiler: and she's actually Clytie Potts from the first book, who everyone assumed died in the destruction of London]].
* EndOfTheWorldSpecial
* EnormousEngine: How do you think a Traction City gets around?
** so much so that they have to eat other Traction Cities to fuel them.
* TheFagin: Uncle.
* FantasticRacism: Between the Scriven and humans.
* FeetOfClay: Both of Tom's heroes. Nimrod Pennyroyal is the slightly nicer. [[spoiler:Relatively: he shoots Tom in the heart, eventually causing his death]], SmallNameBigEgo version. Thaddeus Valentine is the nasty, nasty kind.
** However, Valentine is the more likeable character, almost a TragicVillain, while Pennyroyal is as despicable as Gilderoy Lockhart characters tend to be.
* ForegoneConclusion: [[LaResistance The London Underground]] in ''Scrivener's Moon'' aren't going to stop the reconstruction of London as the first Traction City.
** From what we know of air technology in Mortal Engines, Arlo isn't going to complete his aeroplane [[spoiler: but then he does. It just gets destroyed and the technology banned by religion, making this a bit of a ShaggyDogStory. Some of his comments on 'bird roads' and such do indicate that he has an impact on flight though.]]
* ForgottenSuperweapon: MEDUSA the [[spoiler:city-killing laser]] and ODIN the KillSat.
* ForScience: The Engineers in Fever Crumb. They're still some of the most ethical characters in the entire book. Despite, ironically, trying to avoid emotions and other "irrational" things.
* FriendlyEnemies: Naga and Kriegsmarshal Von Kobold. Naga sends his rival a gift of a bullet-proof vest enscribed with the words 'sorry we missed you' when he learns that the Kriegsmarshal survived an attack from a Green Storm sniper. The Kriegsmarshal, in return, considers Naga more likable than some of his allies in the Traktionstadtgesellshaft.
* FutureImperfect: Plastic idols of Mickey and Pluto, "animal-headed gods of lost America."
** America, incidently, was first discovered in 1924 by Christopher Series/{{Columbo}}, the notable detective and explorer.
*** In a play, 'Niall Strong-Arm' is sent by 'Mad King Elvis of America' to the Moon, where the Moon Goddess, (Princess?) Diana falls in love with him.
**** Reeve is just fond of this trope in general - "blog" is adopted as profanity in ''Fever Crumb''.
***** And, of course, in the same book, the "Hari Potter" cult throw away gag.
* GadgeteerGenius: Dr. Popjoy for creating [[spoiler:Stalker Fang]] and Dr. Zero for [[spoiler:re-resurrecting and improving Shrike to kill the Stalker Fang]].
* GambitRoulette: used a couple of times; it seems just about everything is helping [[spoiler: Anna Fang, resurrected as a cyborg Stalker]] get the control codes to the superweapon.
* GettingCrapPastTheRadar: about triples in quantity in the fourth book. Particularly when [[spoiler: Wren is trying to get aboard Harrowbarrow to delay it from eating New London,]] and is caught by some of its soldiers: "One of the men searched her for weapons, more thoroughly than Wren felt was really necessary (surely they must know that you couldn't hide anything ''very'' dangerous inside your bra?)."
** Although never explicitly mentioned, its obvious that Tom and Hester had (or almost had, due to an interruption) [[PreClimaxClimax sex]] right before [[spoiler: confronting the Stalker Fang]] in the last book
** This is also heavily implied without being stated outright in the second book, ''Predator's Gold'', where Hester passionately kisses Tom after their escape from some villains, then we cut discreetly to another scene, and then we come back to the couple much later, entwined in a loving embrace... And then at the end of the book what went on in between is rather confirmed when [[spoiler: Hester learns that she's pregnant]].
* GoodScarsEvilScars: Played with. Hester has some truly hideous scarring on her face and is... complicated. Her extreme moral ambiguity really stems from her scarring and the event that caused it.
* GreyAndGrayMorality: Both well-played on both sides, and deconstructed in that some people act out of selfish reasons. Surprisingly enough, there are a few JerkAss characters who are simply in it for themselves.
* GrowingUpSucks: Hester, Tom, Wren, Theo, and every single last one of the Lost Boys. Arlo Thrusday to a lesser extent.
* [[HalfTheManHeUsedToBe Half The Woman She Used To Be]]: [[spoiler:Poor, poor Wavey.]]
* HeAlsoDid: The author wrote another steampunk series, ''Literature/{{Larklight}}'' and its sequels. They feature BritishStuffiness, an amiable giant crab, a close-knit family, an [[TrueCompanions equally close-knit]] band of very pleasant SpacePirates, a giant blue lizard in a crinoline, a NinjaMaid, and an ''entire race'' of {{Nice Hat}}s. Not an entire race of people who ''wear'' nice hats, an entire race of people who (most of the time) ''are'' nice hats. We suspect antidepressants.
* HeroesWantRedheads: Tom has had crushes on Katherine Valentine and Freya Rasmussen, but the only one he has ever loved is Hester.
** After falling for[[spoiler:Arlo Thursday, who has black hair,]] in ''A Web of Air'', Fever falls in love with [[spoiler:Cluny Morvish, who has flowing dark-red locks,]] in ''Scrivener's Moon''.
* HeroicSacrifice: [[spoiler:Katherine Valentine]] in the first book. Also, [[spoiler:Naga]] in the last one.
* HistoricalBeautyUpdate: In-universe: Pennyroyal does this to Hester when [[ShowWithinAShow writing about his adventures]] in ''Predator's Gold'', prompting her to exclaim, "is that supposed to be ''me''?" Her disfiguring scar becomes a small, cute scratch on her cheek, for starters.
* IAmYourFather: Thaddeus Valentine and [[spoiler:Hester Shaw, though neither acknowledge it to the other]].
* IDidWhatIHadToDo: Magnus Crome, in particular (I wanted to make London strong!), but also Hester, Thaddeus Valentine, Oenone Zero, Shrike, Anna Fang, Wolfram von Kobold... Usually just makes things worse for everyone.
* IdiotBall: Theo Ngoni does some pointlessly stupid things in ''A Darkling Plain''.
* IGaveMyWord: Once Crome and his people have learned all they can from Shrike, Crome could very well have had him dismantled, but he chooses to let Shrike go, and Shrike has faith that the Engineer will give him his 'heart's desire' - [[spoiler: which is to have Hester Resurrected into a Stalker.]]
* [[IHaveNoSon I Have No Mother]]: [[spoiler: Wren pretty much cuts off all ties to Hester at the end of the third book, and never sees her again.]]
* ImplacableMan: All Stalkers, but ''especially'' Shrike, who gets; hit by multiple times an emplacement-weapon grade Tesla cannon, buried for centuries, torn apart, shot (ineffectively), stabbed multiple times by many different people and other Stalkers (likewise, [[spoiler: though Tom manages to put him into a sort of hibernation for fifteen years by ramming a sword into his damaged chest]]), Battle Frisbee-d (makes sense in context) blown up, ''run over by a city'' (literally), dropped out of an airship into a frozen lake, and [[spoiler:and is still alive in the DistantFinale, where he tells the story]].
* JerkWithAHeartOfGold: Hester in the first book. In the following ones, she's still this, but only with the people she cares for.
* KarmaHoudini: somehow played ''and'' averted with Pennyroyal: he never paid for [[spoiler:shooting Tom and stealing the ''Jenny Haniver'']] but at the end of the last book, [[spoiler: his reputation is ruined and he spends a fair amount of time in prison. Though he does get released and married eventually, nobody ever trusted him enough to publish the one truthful book he wrote, not even his wealthy wife]].
* KilledOffForReal : Employed liberally; a great number of major and minor characters get the chop, usually quickly and horribly. In the first book alone, [[spoiler:Shrike, Anna Fang, Thaddeus Valentine, Kate Valentine, Bevis Pod, Magnus Crome, and ''pretty much the entire city of London'' die]]. Partly subverted as in the course of the second, third and fourth books, some of these characters turn out to have survived [[spoiler: or have been Stalker-ized]], but then at the end of the fourth book (before the DistantFinale) [[spoiler:Pomeroy, Naga, Stalker Fang and, last but not least, Tom and Hester, die]].
* LayeredMetropolis: London has become this in MortalEngines thanks to Quirke, who transformed it into the world's first mobile city. The 7th tier houses the engine district, while St Paul's Cathedral sits on the uppermost tier.
** Later in the series, as we see more and more Traction Cities, we find that they're all layered -- in fact, the number of layers a city has becomes a sort of short-hand for the amount of power and wealth it possesses. Small cities might have just two layers, [[UrbanSegregation with the poor citizens]] sharing the lower tier with the engines and other machinery [[UrbanSegregation while the wealthy live in the fresh air and sunshine above]]. Some of the largest and most powerful cities may have up to a dozen layers (the higher, the more respectable). Only small towns make do with only a single deck.
* LetsGetDangerous: The Guild of Historians at the end of the first book.
* LightningBruiser: tractions cities are very fast(London hits 100 kmph in the first book), and when armed for war can pack insane amount of firepower and armour.
* KillSat: ODIN (Orbital Defense Initiative), used to obliterate cities and make volcanoes.
* LostTechnology: Dovetails neatly with the above Kill Sat and Black Box. Also plays a big role in the setting otherwise: "Old Tech", barely understood technology left over from our own civilization (and several others that followed, and collapsed in turn) is a constant source of headaches for our heroes.
* MacGuffin: The Tin Book is ''[[ChekhovsGun seemingly]]'' one of these for some time.
* MadScientist: Dr Popjoy.
* MadeOfIron: Shrike, who survives being run through with a sword, falling into a ravine, and ''being run over by a city'', among many ''many'' other things. In fact, he's actually older than the Traction Era itself, and has lived through it all.
* MagnificentFlyingMachines: Airships of all shapes and sizes play a major role in the setting, and air travel is heavily romanticised. Air merchants ply the "Bird Roads" in their little tramp ships, seeing the world and having glamorous adventures; nations go to war with fighter-airships and {{Airborne Aircraft Carrier}}s; rich playboys may ride around their mansions in tiny couch-sized blimps. When the secrets of heavier-than-air flight are finally re-discovered later on in the series, all sorts of improbable ornithopters, autogyros, and other rickety flying machines are added into the mix.
* ManchurianAgent: [[spoiler:Shrike in ''Infernal Devices'', programmed to destroy Stalker Fang if Oenone Zero utters the phrase "The moment of the rose and the moment of the yew tree are of equal duration."]]
* ManicPixieDreamGirl: Subverted. At the beginning of the first book, Tom dreams of being pulled from his dull life into a wild adventure possibly involving a pretty girl. He does, but the girl is ''far'' from pretty and the adventure will leave him more homesick than ever.
* MasculineGirlFeminineBoy: Hester and Tom, complete with romantic tension, and especially in the first half or so of ''Mortal Engines''. Tom is a sensitive, emotional, often naive NonActionGuy, while Hester is a BadAss ActionGirl who doesn't talk much and suppresses her feelings. Tom is constantly shocked by the rough world beyond London, while Hester is the one who's seen it all before, has a tough skin, and gets irritated by Tom's difficulty coping until he starts to adjust. As a bonus, Tom is handsome and conventionally attractive, while Hester has a huge disfiguring scar.
** This trope is still in effect further into the book series, though sometimes Hester breaks down and acts in a very emotional way, and Tom toughens up as a result of his adventures, and gets some action-heroics of his own here and there. There are still scenes where they very neatly reverse typical gender-stereotyped roles -- like near the climax of ''Predator's Gold'', where Hester intentionally leaves Tom out of harm's way in order to protect him while she goes off to do violent and badass things to the villains.
* MeaningfulName: Anna Fang may be from the German "anfang", meaning "beginning"; some characters' and vehicles' names may be meaningful (such as the airships ''Jenny Hanniver'' and ''Shadow Aspect'', or the steam powered-ram ship ''Supercolider''), but others are just as often meaningless (there's a minor character called Lurpak. Yes, really. And his first name is Cat.)
** Tom Natsworthy, probably because he starts out as a mere good-for-nothing apprentice.
** In Greek mythology, the medusa was a half-woman half-monster creature who would turn anyone into stone if they looked directly at her. The MEDUSA from ''Mortal Engines'' does do this after a sort ([[spoiler: it's mentioned that there are carbonised statues of people on the lower levels of Panzerstath-Bayrouth, the city London fries with MEDUSA, that were flash-cooked by its intense heat]]), but it mostly just kills everything in it's path.
** In Northern mythology, Odin was the one-eyed god of death. This about says it all.
* MegaMawManeuver: How the cities hunt each other.
* MinoredInAssKicking: The Engineers in Fever Crumb don't let a complete lack of combat skills stop them from showing just how effective they are in a crisis. See Crowning Moment of Awesome.
* NarratorAllAlong
* NeglectfulPrecursors: The Ancients, a.k.a. ''us'', modern 21st-century humans. According to the books, sometime in the 21st century most of humanity wipes itself out in the [[WorldWarIII 60 Minute War]], leaving behind a few miserable survivors, a devastated planet, and a rich cache of malfunctioning death-rays, lethal bio-engineered plagues, and all sorts of other goodies that the humans of the Traction Era keep digging up and killing themselves with millennia later. Collectively called Old-Tech, these remnants of the Ancient civilization keep turning up in every book of the series, usually leading to nothing very good at all.
* NiceGuy: Tom ''embodies'' this trope.
** It's for this reason that 'everybody likes Tom', which is mentioned at least once in every book that features him.
* NiceJobBreakingItHero: If Hester hadn't abandoned [[spoiler: Fishcake]], half of ''A Darkling Plain'' wouldn't have happened.
* NonActionGuy: Tom Natsworthy.
* NoOneCouldSurviveThat: Shrike, several times. [[spoiler:Also Anna Fang. Subverted in that she actually dies, and is brought back as a Stalker.]]
* ObliviousToLove: Is Cluny the only one who hasn't worked out [[spoiler: that Fever's in love with her]]?
* OfficialCoupleOrdealSyndrome: [[spoiler: Tom and Hester ''and'' Katherine and Bevis. [[KillEmAll It really doesn't end well...]]]]
* OmnicidalManiac: [[spoiler:Stalker Fang.]]
* OppositesAttract: NonActionGuy Tom Natsworthy and DarkActionGirl Hester Shaw.
* ParentalSubstitute: Anna Fang is hinted to be seen as this by Tom and Hester: in the first book, a conversation with Anna reminds Tom of his late mother, and in the second, Tom and Hester put a picture of Anna in an alcove aboard the ''Jenny'' meant for pictures of parents...though this is partially due to neither of them having any pictures of their own.
** Also, Shrike wants to be this for Hester [[spoiler: and often refers to her as "his daughter"]].
* {{Precursors}}: The Ancients, i.e. us.
* RidingTheBomb: More like "piloting the bomb". The fanatical Green Storm employ Tumblers, piloted heavy ordnance dropped from airships.
* RightForTheWrongReasons: Some of Professor Pennyroyal's crazy theories turn out to have a grain of truth to them -- [[spoiler:There are no savages or bears in America, but there are green, habitable areas; there are no "parasite cities", but there are the Limpets and the Lost Boys]] -- no thanks to any particular efforts on his part, however...
* RunningGag: In the first book, characters tend to mispronounce Tom's family name, including Anna Fang when they first meet. His encounter with [[spoiler:Stalker Fang]] in the second book [[ShoutOut references]] this.
* ScavengerWorld
* ScrewTheRulesIHaveMoney: The Huntsmen of Arkangel will happily pay rewards to anyone who gives them co-ordinates for Traction Cities they can hunt, but Tom considers this practise a betrayal of Municipal Darwinist principles.
* SelfParody: [[ShowWithinAShow Professor Pennyroyal's books]] make use of common adventuring tropes in an exaggerated and often humorous way. Particularly notable is his book, ''Predator's Gold,'' which he writes during the events of ''Predator's Gold'' (the real-life book) and which basically presents Pennyroyal's own skewed, exaggerated version of the same (he was just trying to improve the pacing, honest!) Amongst other things, he turns himself into a stereotypical action hero, and gives Hester a sort of Hollywood Make-over (prompting her to exclaim, "is that supposed to be ''me''?").
* ShipperOnDeck: Tom likes to tease his daughter about her relationship with Theo Ngoni. Anna Fang likes to tease Hester about her relationship with Tom. [[spoiler: Disturbingly, Stalker Fang does the same while trying to destroy the world in the final novel.]]
* ShowWithinAShow: In ''Predator's Gold'' the historian Pennyroyal writes a book, ''also'' called ''Predator's Gold,'' which covers pretty much the same events as the Real Life book -- only from Pennyroyal's own, ah, ''[[BlatantLies unique]]'' perspective. This has both dramatic and comical consequences. Amongst other things, it's used to parody common adventuring tropes, and much is made of the HistoricalBeautyUpdate / HollywoodHomely treatment he gives his version of Hester...
** Pennyroyal becomes a recurring character, and his books generally play a not insignificant part in the plot of the series.
* SchizoTech: Heavier than air flight is literally re-invented in the series. It's primitive and unreliable, whereas drive systems that can move entire cities at motorway speeds across uneven and often constantly shifting terrain are universal.
** ''Hot air balloons'' are reinvented in Fever Crumb. Though they only get one use.
** In ''Web Of Air'' The City Of London adopts a policy of [[spoiler:killing off anyone researching flight and later an ongoing policy of creating religious prohibitions against it, because it represented a clear danger to the new traction city.]]
** The Green Storm takes this UpToEleven. Expect to see massive air-destroyers with tech modern humans won't develop today, dropping kamikaze Tumblers and firing more guns than a fleet of AC-130s, providing backup to cavalry armed with machine guns and Killer Zombie Robots while they're being strafed with armed Wright Flyers, which are in turn coming under attack from undead birds and fighter airships. Yes, seriously. Like an F-16 in airship form.
** In the DistantFinale, Shrike awakens to see that human civilization has become a peaceful, agrarian society living in simple dwellings amid the ruins of the old traction cities...with gravity-defying hovercraft floating around.
* ShoutOut: Almost too many references to name, recalling all kinds of fact and fiction.
** The city of Brighton has an aircraft guidance system consisting of a large wheel with lights on it. It's called the "Pharos Wheel", as in Ferris Wheel and Tower of Pharos.
** Two mechanics in the mercenary fighter squadron "Flying Ferrets" are named Algy and Ginger. These are two major characters in the British book series ''Biggles'', which was about fighter pilots.
** Again, the steam-ram ship ''Supercollider''. "Collider" is a specific type of particle accelerator.
** The god Poskitt is named for Reeve's real-life friend Kjartan Poskitt. Mortal Engines has many {{Shout Out}}s in its vast, varied and frequently invoked pantheon, including "[[http://en.wikipedia.org/wiki/Margaret_Thatcher The Thatcher]], [[TakeThat six-armed Goddess of unfettered Municipal Darwinism.]]"
** Many cities are {{Shout Out}}s:
*** London is based on the real London, complete with St Pauls and a vertical transport parodying the Underground.
*** Brighton is likewise full of references to Reeve's hometown.
**** And not very flattering references. Reeve has mentioned that his later-created city of Mayda is in part a reflection of the nicer side of Brighton.
*** Wolverinehampton, an ugly place with huge jaws, is a predator city named after Wolverhampton.
*** Tunbridge Wells has become an amphibious town known as Tunbridge Wheels.
*** Grimsby is thought lost, deep under the ocean.
*** Many German cities have their original names with titles like "Traktionstadt" (traction city), "Jagdstadt" (hunter city) and "Panzerstadt" (literally "armoured city", recalls Panzer, German for tank) added, such as Panzerstadt-Weimar. Bilingual Bonus.
** Shoutouts involving vehicle names include:
*** The ''13th Floor Elevator'', Thaddeus Valentine's armoured airship, is named after a sixties psychedelic rock band.
*** The Flying Ferrets fighter ''Itsy Bitsy Teeny Weeny Yellow Polka Dot Machiney'' is named after a popular song involving a bikini.
*** The airship ''Shadow Aspect'' is named for an archetype in Jungian psychology.
*** The airship (and centuries earlier, boat) ''Jenny Haniver'' is named after the nickname given to fake mermaids often seen in curisoity shops. Fitting, as both vessels are actually made of scraps from others.
*** The Green Storm airship ''Hungry Ghost'' is named for a traditional Chinese festival.
*** The Green Storm airship ''The Sadness of Things'' is named after a painting.
*** The limpet ''Ghost of a Flea'' is named after a painting by William Blake.
*** The limpet ''Naglfar'' was a ship in Norse mythology made of the ''toenails of the dead''.
*** The "Mokele-Mbembe", named for an African legend about a (relatively) small jungle sauropod.
** Then there's the passing mention of the [[Franchise/HarryPotter Hari Potter]] cultists in Fever Crumb, as mentioned in FutureImperfect...
** The Green Storm parallels the Cultural Revolution; this is most apparent in some of the slogans and revolutionary songs that are named.
** The actors at the travelling theatre in ''A Web of Air'' worship a goddess named [[http://en.wikipedia.org/wiki/Royal_Academy_of_Dramatic_Art Rada]].
** Some of the ancient technology- the 'seedy', a shiny round platter, as well as references in popular books to 'eye-pods' which stored music on thousands of tiny gramophone records. Also the buses in ''Fever Crumb'' require the passengers to buy the shell of an oyster in order to ride one.
* SingleWomanSeeksGoodMan: Already there in the first book but especially apparent in the following ones, where Hester is head over heels for the [[NiceGuy nice]] NonActionGuy Tom Natsworthy.
* SlidingScaleOfIdealismVersusCynicism. Way, ''way'' over towards the "cynicism" end. The very, very few optimistic characters (Tom, Wren, possibly Oenone Zero) are shown again and again to be completely out of their depth, while the pessimists, nihilists, slave-dealers, compulsive liars, juvenile delinquents, mechanical horrors and violently depraved psychopaths are in their element. And somehow, it WORKS.
* SmallNameBigEgo: Nimrod Pennyroyal.
* SocialDarwinist: As in ''Municipal'' Darwinist. Survival of the fittest city.
* StandardSciFiFleet: The air fleets of the Green Storm and the cities they fight fit the conventions of this trope quite well -- except that they fight [[TheSkyIsAnOcean in the air]], rather than [[SpaceIsAnOcean in space]], of course. Airships are separated into classes ranging from small fighters (not fighter ''planes'', but small, armed lighter-than-air ''ships'') to corvettes, destroyers, and even dreadnoughts depending on their size, armament, and general level of danger they pose to any characters that happen to get in their way.
* TheSpock: The engineers in Fever Crumb. Fever herself is slowly Becoming TheKirk
* StalkerWithACrush: Yes, Shrike [[spoiler: wanted Hester as a daughter]], but it's close enough (and the IncrediblyLamePun writes itself).
* {{Steampunk}}: Often lumped into this category though it really doesn't fit the Steampunk definition very well (its technologies more closely resemble DieselPunk). Furthermore, Reeve dislikes the genre for its backward-looking-ness.
* StevenUlyssesPerhero: A girl named Oneone Zero grows up to be brilliant at building and programming {{Cyborg}}s. And yes, Oneone Zero is her actual birth name -- though it's not uncommon for characters in this setting have names based on products or concepts from the 21st century (the civilization of the "Ancients," from their perspective).
** Ultimately subverted: Oneone's medical skills (again, she works with ''{{cyborg}}s'') turn out to be just as relevant to the plot as her electronics skills. Also, despite her computer-themed name, which one would expect to be associated with cold, rational logic, she turns out to be one of the kindest and nicest characters in the books.
* StreetUrchin: The Lost Boys are half Literature/OliverTwist, a quarter JackTheRipper and a quarter [[http://en.wikipedia.org/wiki/Stingray_%28TV_series%29 Stingray]], living in a submerged city and looked after by "Uncle", a delusional Fagin-esque techno-wizard in pink bunny slippers with steel toecaps. They're really not very nice people at all.
* TakingYouWithMe: [[spoiler:General Naga]]. And HOW.
* TalkingIsAFreeAction: Tom manages to say "A Nuevo-Mayan Battle Frisbee!" while seeing one in flight. [[SaidBookism "Gasps" it, too.]]
* TastesLikePurple: Fever, like all Scriven, is a synesthetic, meaning she can see scents.
* TemporaryLoveInterest: Kate Valentine, who [[spoiler:gets accidently and brutally killed by her own father]] and Freya Rasmussen for Tom. Also, Wolf Kobold for Wren.
* ThatManIsDead: "I am not [[spoiler:Anna Fang]]. We are wasting time. I wish to destroy cities." (Admittedly in this case the character did literally die.)
* TheChick: Tom and Wren Natsworthy, probably the only main characters who aren't happy with theft, violence and casual murder.
** In the first book, Katherine Valentine and Bevis Pod, in contrast to most of the Londoners.
** In the second and third, Freya Rasmussen, in contrast to Hester.
* TinMan: The Engineers are revealed to be this in Fever Crumb. Most of the time they're TheSpock but when it matters they've got their sensitive side even if they don't really know how to deal with it. Hell compared to the cutthroats and ruffians that take up most of London's screentime they're practically TheChick. Which is ironic, as Fever Crumb is the only female Engineer, EVER.
* TogetherInDeath: Invoked by Hester at the beginning of the second book. [[spoiler:Played straight at the end of the fourth]].
* TomboyAndGirlyGirl: Philip Reeves likes to contrast [[TomBoy Hester]] with a much more feminine character in each book: Katherine Valentine in the first, Freya Rasmussen in the second and the third, and even Hester's daughter Wren in the third and the fourth.
* TragicVillain: [[spoiler: Valentine ultimately turns out to be this by the end of the first book.]]
* TrrrillingRrrs: Cluny, full stop.
* UglyGuyHotWife: Inverted with Tom and Hester. She's the ugly one and he's considered handsome.
* UnderwaterBase: Grimsby.
* UrbanSegregation: Goes hand-in-hand with the widespread use of the LayeredMetropolis trope. In the first book, Tom being from Tier Two defined him as a respectable citizen of London (at least, in the eyes of people from smaller towns); the lower of London's seven Tiers were populated by progressively poorer workers. Every Traction City is segregated in this way, however many layers it may have (some only two, some a dozen). The topmost Tier will be occupied by mansions, landmarks, and the Mayor's residence; the next one below may have respectable businesses and offices; below that -- working class residences. On the meaner cities, the lowest tiers may house slaves; on the nicer ones, some literal social climbing may be possible. Because the lowest tiers also house the giant engines that move Traction Cities, they are usually very unpleasant places to work and live, and of course only the top Tier gets full sunlight and fresh air.
* UsedFuture: Played believably, once you accept the basic premise is cities eating each other.
* VillainProtagonist: Hester Shaw, though it all depends on how you see the Anti-Traction League as opposed to London. By the end of the book she's [[spoiler: definitely not a villain in any sense]]. In later books, she [[spoiler: sort of slides back down toward the villain side of things]].
* [[WarElephants War Mammoths]]: The Arkhangelsk use these in Scrivener's Moon.
* WorldHalfEmpty: The basic premise is living on a giant mobile city, eating cities smaller and slower than you and running away from bigger ones. If your city gets taken by a bigger and meaner one, it will be taken by force, completely looted, stripped down for raw materials and its population enslaved.
** In the third and fourth books, the antagonism between Traction Cities and the Anti-Traction League turns into a total war between the Traktionstadtgesellshaft, a union of militarised German cities and their allies, and the Green Storm, a band of psychotic air-pirates who overthrow the previously peaceful League leaders and turn it into a totalitarian state obsessed with the annihilation of cities. Aboard any Traction City, even non-militarised pleasure cities, you're liable to be blown apart by man-piloted heavy bombs, fleets of giant airships and psychotic undead cyborgs armed with finger-blades; fighting for the Green Storm, you're likely to be either piloting one of the bombs or attempting to fight conventional battles against ''war-rigged mobile cities'', and if (when) you die on the battle lines, may have the bad luck to get your corpse turned into one of the aforementioned psychotic undead cyborgs and have to do the whole stupid thing again.
* WretchedHive: [[spoiler:Brighton after the Lost Boys take over]] is described as this.
* WrongGenreSavvy: In ''Infernal Devices'', Boo-Boo Pennyroyal has watched too many romantic tragedies at the opera, and is convinced that her slaves and servants are at constant risk of falling into doomed love affairs and running away or killing themselves out of grief and heartbreak. She tries to discourage this, but is also secretly eager to play the role of the kindly, understanding mistress and matchmaker. She ends up being kind towards Wren and Theo as a result, even though they're actually in a Dieselpunk adventure story, romance is far from their top priority, and they end up being rather annoyed with Boo-Boo ("SheIsNotMyGirlfriend" being very much in effect).
* {{Yandere}}: Hester in the second book onwards.
* [[ZeppelinsFromAnotherWorld Zeppelins From A Post-Apocalyptic Future]]: Heavier-than-air flight has all but died out and been replaced by airships. However: Ornithopters and gyrothopters have just been reinvented in A Darkling Plain, used effectively by the Flying Ferrets. In A Web of Air, heavier-than-air flight is achieved by Arlo Thursday [[spoiler:and then promptly crushed to prevent it being used against the newly-created traction cities]].
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