''House of Suns'' is a novel by Welsh Sci-fi author Creator/AlastairReynolds, set in [[BroadStrokes more or less]] the same universe as the novella [[http://subterraneanpress.com/index.php/magazine/fall-2008/audio-thousandth-night-by-alastair-reynolds/ Thousandth Night]].

Six million years in the future, the entire galaxy is a UsedFuture. Tens of thousands of human civilizations have risen and fallen. The galaxy's been united under a single banner [[EternalRecurrence too many times to count]]. In the face of deep time, each galactic federation always falls. No one group endures.

Except the Lines. Individually known as "shatterlings", the Gentian Line is composed of [[DwindlingParty slightly under]] [[SendInTheClones a thousand clones]] made from a woman who lived in the 31st century. They individually [[WalkingTheEarth roam the galaxy]], flitting from star to star at near the speed of light, skipping over the ages via {{time dilation}}. Their purpose is the explore and catalogue civilizations. Every quarter million years they all come together to share their experiences and combine their knowledge. They've existed for the past six million years, witness to the constant grind of civilization.

Campion and Purslane are two shatterlings who are running late to the most recent Line reunion, having been delayed for a variety of reasons. Fortunately, during their travels, they manage to rescue an amnesiac android named Hesperus. Returning him to the [[MechanicalLifeforms Machine People]], a society of advanced robots, would put the Gentian Line on very good terms with them, so Campion and Purslane figure that will excuse them for their lateness to the Reunion.

Things aren't quite what they seem. Hesperus is discovered to have a [[UnroboticReveal human arm]] underneath his metal exterior, a fact that even he can't explain due to his amnesia. And another guest of theirs mysteriously dies during the journey to the reunion. But worst of all is that when they get to the Reunion planet, they find it utterly wiped out. Turns out, someone is attempting to wipe out the Line. Someone who has intimate knowledge of the Line's secrets, and who keeps a ''very'' long grudge.
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!! This novel provides examples of:
* AIIsACrapshoot: Subverted: [[spoiler:In the past, a robot culture emerged. Humanity, fearing this trope, created a virus which infected all the robots with a kill-switch, to be used only in case humanity felt it needed to be. The virus malfunctioned and activated anyway, initiating a genocide. The House of Suns erased all references to the event from history and maintain a conspiracy to keep it that way.]]
* AlienSky: The world that the novel starts on has a special atmospheric bubble which, at night, amplifies faint stars and nebulae, creating a very colorful night sky.
* ArtificialGravity: Used by the starships to propel themselves and to protect their occupants from the crushing force of their thrust.
* BigDumbObject: The Vigilance.
* BodyHorror: The far-future torture technique called "sectioning", in which the victim is gradually cut into smaller and smaller pieces while being kept alive (with advanced technology).
* CoolStarShip : The ''Silver Wings Of Morning''. Basically, the starships from the ''Revelation Space'' series turned UpToEleven.
* CreativeSterility: The original Machine People couldn't create art, but were fascinated by it.
* DeflectorShields: Used throughout the novel. A ubiquitous technology during the time of the novel. Also used for intertial dampening, as a ship's shields can be projected internally around its inhabitants, allowing extremely high-g maneuvers that would normally render everybody inside to jelly.
* DysonSphere: The Gentian Line's stardams, which can ''contain a supernova.''
* EndangeredSpecies: Though not a "species", per se, this is pretty much what happens to the Gentian Line. They went from 1000 members to only ''fifty'' after the initial attack on them, and with someone actively gunning for them, they are in real danger of being wiped out forever.
* FasterThanLightTravel: [[spoiler: Used at the end, via a Prior artifact. Otherwise, all travel is by slower-than-light ships.]]
* GhostPlanet: Implied to be very common throughout the galaxy. Since the various descendants of humanity have been cavorting around the galaxy for the past six million years, there are plenty of planets that once played host to technological civilizations only to leave nothing behind but ruins.
* HumansAreTheRealMonsters: [[spoiler:The Lines come into contact with a curious, benign robotic civilization spawned from human technology. The Lines develop a virus to disable the robots if they pose a threat to human civilization, triggered remotely.]] Except, [[spoiler: The virus suddenly goes off and begins wiping out the civilization, and the Lines desperately cover it up by ignoring the robots, and then cover it up, by wiping out entire human civilizations and indvidual Lines.]]
* TheFogOfAges: The long-lived protagonists, considering they've lived through ''six million years'' (though, admittedly, only a couple tens of thousands of those concious). They routinely re-arrange/edit their memory. It's implied that they could hold all of their memories at once, if they wanted to, but having that many memories would affect their personality so drastically that most choose not to. Most the long-lived characters tend to hold a rough cliff-notes version of their memories in their heads, but not any of the details; the main character Campion intentionally prioritizes his "recent" memories, which in part drives the main plot.
* HumanitysWake: Due to the sheer number of civilizations that have come before, it seems you can't go ''anywhere'' in the galaxy without bumping into some planet that was colonized, terraformed, rose to prominence, became the center of a galactic civilization, then died out, leaving the ruins to be colonized again by whatever evolved in the three million years that has passed...
* HyperspaceIsAScaryPlace: Well, wormholespace anyways.
* LaserGuidedAmnesia: Becomes a major plot point. See also TheFogOfAges entry above.
* MechanicalLifeforms: The Machine People, a race of human-looking androids with a little bit of [[ClockworkCreature clockwork features]] thrown in for flair. Despite having been around for millions of years, undergoing their own MechanicalEvolution, there's still [[FantasticRacism people who think]] of them as [[JustAMachine nothing more than mindless automatons who just ''imitate'' sentience]].
* MegaMawManeuver: Used by a pirate attempting to capture Campion and Purslane's ship.
* OppositeSexClone: Half the members of each of the Lines.
* OurGiantsAreBigger: Curators of the Vigilance
* PortalNetwork: [[spoiler:The First Machine that Campion meets tells him that there are wormholes throughout the Andromeda galaxy which lead to different galaxies throughout the universe. It also speculates that the 250-million-light-year-wide [[UnnecessarilyLargeInterior Bo÷tes void]][[http://en.wikipedia.org/wiki/Bootes_Void]] could actually be full of galaxies connected by wormholes, but that each galaxy is otherwise blocked from the rest of the universe so they can use their wormholes for pseudo-FTL travel without violating causality.]]
* ReactionlessDrive
* ReallySevenHundredYearsOld : The Shatterlings are about 6.4 '''million''' years old, though "only" a couple hundred thousand of those are spent awake.
* RubberForeheadAliens: Played with, as the entire population of the Milky Way Galaxy can trace its ultimate ancestry back to Earth.
* SendInTheClones: The shatterlings are all clones of Abigail Gentian; however, they've all been slightly modified, [[OppositeSexClone and some are male]], so there's some variation. Better to think of them all as siblings who remember being the same child.
* ShoutOut: This book is pretty much every single Alan Parson's Project song title smashed into a Space Opera screen play.
* SpaceOpera: And how!
* SternChase: Across 60,000 light-years of interstellar space.
* ThatsNoMoon: The protagonists stop at a ringed gas giant because they heard about a spaceship salesman who lives there. They enter the atmosphere and find that he only has a few ships to sell. After some coercion, he shows them his entire collection of ships, [[spoiler:which were hidden inside and disguised as part of the gas giant's ring system.]]
* ThereIsNoKillLikeOverkill: When the shatterling's reunion world is destroyed by the entities trying to wipe out the Gentian Line.
** The world is [[KillSat bombarded from orbit]] and it's [[DeathFromAbove atmosphere is boiled off]] from the sheer energies of the onslaught. Normally that'd be enough to kill anyone, but the aggressors just keep on going, continuing to bombard the planet [[DeathInAllDirections until the crust melts completely]]. ''[[HumiliationConga They still keep on going]]'', pumping so much energy into the planet that it literally [[EarthShatteringKaboom just expands from the heat and disintegrates in a slow-motion kaboom]].
* TimeDilation: The main reason the Gentian Line has persisted for so long. Also, an unavoidable consequence of pretty much ''any'' kind of space travel, since if you want to get anywhere in a reasonable amount of time (read: within a couple thousand years), you pretty much have to crank up the g's until you're near lightspeed.
* UnusualUserInterface: Palatial, a sort-of holodeck. It's a small room, but as you walk in you are immersed in a vibrant, computer-generated world. Your brain is continually scanned while you are in it, so the world constantly adjusts and changes according to your wishes.
* UsedFuture: The ships used by the Gentian Line are often millions of years old. There are also millions of planets lying around that have been terraformed, then left forgotten, then rediscovered and colonized, then forgotten, then rediscovered...
* WhatHappenedToTheMouse: The minor character at the beginning of the novel, Dr. Meninx, who is the unwelcome guest that delays the main characters at first, setting off the whole plot. [[spoiler: He dies mysteriously during a voyage, after previously acting afraid of Herperus and evasively implying that he had reason to want to kill him. However, it's revealed that Hesperus ''didn't'' murder him, so the characters start to trust Hesperus...and the fact that Dr. Meninx died in the first place is never brought up or questioned again. Literally the whole point of his death was to temporarily cast suspicion on Hesperus, [[RuleOfDrama in order to further the plot slightly]].]]
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