* AluminumChristmasTrees:
** During the London riots, Mallory sees a team of steam-engines of Crimean War fame pulling artillery guns. In RealLife, [[http://en.wikipedia.org/wiki/Traction_engine the traction engine]] had already been in production for farm and circus caravan use by the 1850s, it would have been trivial to adapt them to pull guns and [[http://steamtraction.farmcollector.com/multimedia/image-gallery.aspx?id=42364&seq=7 at least one of them operated in Crimea]].
** Scheduled steam carriage services existed for a brief period in the 1820s and 1830s until the Turnpike and Red Flag Acts effectively quashed them in favor of horse-drawn wagons and railroads.
** The [[http://en.wikipedia.org/wiki/Great_Stink Great Stink]] took place in real life, just three years later and minus the riots.
** Edo Japan possessed clockwork dolls known as ''[[https://en.wikipedia.org/wiki/Karakuri_puppet karakuri]]'' (albeit not as sophisticated as the Engine-driven one in the book).
* GeniusBonus: Karl Marx is the leader of a communist Manhattan city-state. Historically, Marx did spend some time living in New York City as a journalist for ''The New York Daily Tribune'' from 1852 until 1861, publishing his political ideas and thoughts on important issues of the day.
* GenrePopularizer: For SteamPunk, establishing many of its familiar tropes and conventions.
* InferredHolocaust: The steampunk dream of a Victorian information age is somewhat deconstructed by the heavy hints that they're using it to catalogue people for the purposes of the then-popular doctrine of eugenics. [[spoiler:The ending (set in the 1990's) implies that what's left of humanity only exists as simulated information.]]
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