[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/diaspora_greg_egan.png]]
A PostCyberpunk hard science fiction novel by Australian author Creator/GregEgan. First published in 1997, it is a SpiritualSuccessor to his 1994 novel, ''Literature/PermutationCity''. One of the chapters was expanded from an earlier short story of Egan's, called "Wang's Carpets".

Not to be confused with the 1985 novel ''Literature/{{Diasporah}}'' by W.R. Yates.
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!!The novel provides examples of:

* AuthorFilibuster: The treatment of the conflict between Citizens and Fleshers in the early chapters is so one-sided that one gets the feeling Egan was trying to be the Creator/AynRand of the transhumanists, or at least the Bizarro [[Manga/GalaxyExpress999 Leiji Matsumoto]].
* CessationOfExistence: Generally presented as a voluntary option for any being which has achieved everything they might have set out to accomplish. In the end, having reached a kind of literal end of all things, Yatima and Paolo consider their choices. Paolo [[spoiler:accepts Cessation; ''"That's not death. It's completion."'']] Yatima [[spoiler:chooses to spend the rest of eternity in abstract research. ''In the end, there was only mathematics.'']]
* ChekhovsGun: [[spoiler:A sphere becoming a torus in five-dimensional space is the key to unlocking a path to other universes]].
* DigitalAvatar: How Citizens appear to one-another inside their Polises.
* DownerEnding: After unknown billions of years spent hunting through trillions of alternate universes, Paolo and Yatima utterly fail to find the Transmuters. They have no way home and realize that humanity would have evolved beyond all recognition in their absence anyway, so Paolo commits suicide and Yatima retreats into a virtual reality to study mathematics for all eternity.
%%* DuplicateDivergence: A natural consequence of the Carter-Zimmerman Polis's titular Diaspora.%%Quotes aren't context. Explain how this applies.
%%-->After the first fifty years, his Earth-self had begun to hold things back; by the time news reached Earth of the Fomalhaut clone's demise, the messages had become pure gestalt-and-linear monologues. Paolo understood. It was only right; they'd diverged, and you didn't send mind grafts to strangers.
%%* {{Expy}}: The Fleshers are Creator/StanislawLem's Dichoticans in all but name.%%How?
* EverybodysDeadDave: Implied, though not confirmed; the last scene of the novel takes place billions of years after the previous one, Yatima and Paolo have traveled through ''trillions'' of alternate universes in pursuit of the Transmuters, and wound up empty-handed. It's unlikely that they'll be able to get back to their home universe, and even if they do, after billions of years, both Yatima and Paolo agree that humanity has almost certainly evolved into something completely unrecognizable, if it even still exists. They talk it over, and make their decisions: [[spoiler:Paolo commits suicide, leaving Yatima the last recognizable descendant of the human race. Ve retreats into the Mines, a solipsistic virtual environment where ve will spend the rest of eternity studying mathematics.]]
* FormerlySapientSpecies: The Dream Apes' ancestors deliberately removed their capacity for speech and most of their sapience in a wholesale renunciation of modern society.
* AFormYouAreComfortableWith: When the Diaspora reaches the second [[AnotherDimension macrosphere]], two of the protagonists are approached by something that appears to be Hermann. Which freaks them the hell out, because Hermann didn't come with them. The "Contingency Handler", as it calls itself, explains that it chose this form ''precisely'' because it knew that ''they'' would know it couldn't actually be Hermann -- it's actually a nonsentient AI designed to greet new arrivals in this universe.
* InvisibleAliens: Why can't we find any alien races in the Milky Way? They all ran away from the ensuing disaster.
%%* TheMetaverse: Basically what each Polis looks like to its inhabitants.
* MoreThanThreeDimensions: The protagonists discover that subatomic particles actually contain portals to a five-dimensional universe -- whose subatomic particles contain portals to another three-dimensional universe, and so on.
* SpeculativeFictionLGBT: Most of the characters are gender-neutral, although to be fair, that's because most of those characters exist as software and were created as such, having never been in an actual homo sapiens body.
* StarfishAliens: Several species are so alien they can only be communicated with through 'bridgers': Citizens who clone themselves repeatedly, with minor alterations in each iteration, until they are themselves utterly alien. Messages are then sent back and forth down the line of clones, each one translating for the next in terms they can understand.
* {{Transhumanism}}: There are three main forms of humanity, each with several subgroups:
** '''Citizens''' are digital humans living in a collection of giant virtual reality universes, called Polises. The majority of the novel follows the actions of a small group of Citizens.
** '''Fleshers''' are biological humans, which include those who evolved naturally from ''Homo sapiens'' (called "statics") and a multitude of bio-engineered humans including "dream apes", which have had language capability engineered out of them.
** '''Gleisner Robots''' are digital humans living in the real world but separate from the fleshers. They inhabit robotic bodies and spend most of their time in space -- or daydreaming on the Moon in one case.
* TranslationTrainWreck: Yatima finds it very difficult to speak one-to-one with fleshers who have evolved completely alien viewpoints.
* {{Utopia}}: The Coalition of Polises... rather more like the Classical Greek polises wished they were like than they ever were actually like. A post-cyberpunk CrystalSpiresAndTogas. An extropian [[Literature/AtlasShrugged Galt's Gulch]]. All of the polises seen in the story were clearly designed to provide equal computing resources to all citizens thereof, and the polis hardware is unimpeachable in doing just that.
%%* WeHaveBecomeComplacent: Implied to be the final state of all civilizations.
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