The Volga Rules is the sequel to 1636: Kremlin Games, itself a side-novel in the Ring of Fire alternate history series. In the former book, the Russian government hired a frequently drunk and depressed up-time Grantville resident Bernie Zeppi (whose mother died following Grantville's relocation to 17th century Europe due to the lack of modern medicines) to come east and help bring the wonders of modernity to mother Russia. Thanks to his experiences with the horrors of medieval serfdom and downtime seasonal plagues, Bernie snaps out of his depression and helps the Russians achieve some impressive advancements; however, even as he helps to introduce 17th Czarist Russia to 20th century American sanitation, road-building, radio, and weaponry, the ideas that he brings with him become the basis of a political crisis within Russia, one that (at the end of Kremlin Games) boils over into a civil war between the powerful director of the Bureaus, Shremetev, who is opposed to democratic reforms and emancipation of the serfs and the moderate Czar Mikhail, who ends up emancipating the serfs. Now the Czar and his followers have fled to the foot of the Ural mountains to build up a new Russian government in exile while Director Shremetev enacts Stalinist purges to ensure his control of the state and root out Czarist loyalists and radicals. Shremetev has most of the advantages as the majority of the army and the technological infrastructure created by Bernie and his compatriots are under his control, but due to the fact that he has built his entire course of action on the claim that the up-timers have used witchcraft to force the Czar to support their vile reforms he must attack in a circuitous manner to maintain that illusion and prevent the Army (many of whom still loyal to the czar in concept though believing he is bewitched) from turning on him. Meanwhile as Shremetev's playing Stalin and the Czar is holed up in the back of beyond, Russia is coming apart at the seams as all the various disparate groups that have been held together by the Czar's might are clamoring for independence and many others are fearful of supporting the Czar or the Director and have sought to strike out on their own. All in all, Russia is a mess and if the forces of reform and liberty are to succeed then not only will they need to use all their industry, political acumen, and ingenuity but they're going to have to compromise.
I really liked what the team of authors did with this one. I don't know if it's because this has been a long-gestating novel, but I was impressed with the level of thought that they put into the political complexities of the Russian Civil War (and of a Russian Constitutional Convention) and how the various compromises compare to the experiences of the United States of Europe (in the Ring of Fire universe), whose own formation was a strange series of starts, mis-starts, compromises, and fait accomplit reforms. Likewise, they do a lot of thinking about the complexity of throwing semi-modern weaponry into what is otherwise a highly feudal-medieval system of warfare. The Russians on both sides have repeating rifles at their disposal that are essentially World War 1 level tech, but their artillery and other areas lag far behind. Whereas in the main-line books, the USE has a sufficiently robust industrial and technological base that it has been advancing on just about every technological concept conceivable, the Russians just don't have the base of educated personnel or industry and thus they have to pick and choose and it makes things... unusual and means that this book has a lot more technological innovation going on than most of the recent novels. I also liked the new characters (particularly the ex-serf villagers) and the authors' decision to fade Bernie (who was an okay but not great character) into more of a background role. The writing is also less silly (the first book had an extended Rocky and Bullwinkle-related series of jokes that I appreciated as a fan of the old cartoon but ultimately felt kind of forced) and that helps with the challenging situations our protagonists face. All in all, this is a really solid addition to the Ring of Fire series (particularly compared to the French and English side novels) and pushes the Russia storyline forward significantly (and with certain plot events near the end, it may end up merging with the main storyline as Russia East potentially allies with Sweden and the USE against Russia West and Polish-Lithuania), even getting into 1637 (and if you're wondering, no, the story doesn't even mention the Ottoman War (though the ongoing USE-PLC war is mentioned without details repeatedly), which is... strange, particularly since the Russians get a loan from the Bank of Austria at one point; I suspect that because the early drafts of this book were done long before 1636: The Ottoman Onslaught they chose to do their best to avoid the issue entirely and prevent any sort of retcon problems) for the first time in the series to date (OMG! That is one monster of a parenthetical phrase, sorry, but not sorry enough to fix it). Finally, just want to note that it's got a map with Swedish Livonia on it; earlier maps, particularly the one from 1636: Kremlin Games (which also appears here), show Swedish Ingria (in modern day terms: northern Estonia and the portion of Russia around St. Petersburg, which was founded by Peter the Great in the 18th century on the site of the Swedish fortress of Nyenskans, which appears several times in this story) but PLC Livonia (that is, modern day southern Estonia and northern Latvia), which makes no sense since Sweden conquered Livonia in 1629, 2 years before the RoF, while it's conceivable the PLC might've retaken the territory, none of the stories to date have mentioned it and such an attack would undoubtedly have opened a second front in the Polish War and probably forced the Danes to enter the war as it would be an attack on Union of Kalmar territory, so good work to whoever realized that they'd made a mistake and fixed it.