A Fantasy series by Charles Stross, about a journalist named Miriam Beckstein who finds an Alternate Universe stuck in Medieval Stasis where her long-lost family are powerful traders who can travel between dimensions. There are six books so far: The Family Trade (2004), The Hidden Family (2005), The Clan Corporate (2006), The Merchants' War (2007), The Revolution Business (2009), and The Trade of Queens (2010). They are now available in a new edition that combines them into three volumes (The Bloodline Feud, The Traders War, and The Revolution Trade), with some minor changes to the text.The series was originally planned as four very long books, but the publisher got cold feet about the length of the books and insisted they be broken up into multiple volumes. The six books published so far started out as the first two books of the original plan. Stross is currently writing the "next generation" sequels (Dark State, Black Sky, and Invisible Sun).
This series provides examples of:
Action Mom: Miriam's adopted mom and real mother has a shotgun hidden in her wheelchair.
Miriam's Earth is also slightly alternate, as revealed in Book 5. Chemical Ali killed Saddam Hussein before the Iraq War even began and Paris Hilton's funeral is dominating the news. Also Robert Bork is Chief Justice of the SCOTUS, and there was apparently an incident of nuclear terrorism in Italy in the 1970s.
Alternate Universe: and there isn't just one; by book five, a number of others have been documented.
It's worth noting that the series is quite a brutal Deconstruction of the usual "Alternate Universe" setting. The logistical and geopolitical consequences are explored quite thoroughly.
Action Girl: Downplayed with Miriam, she can't take anyone down during a fight, but she sure shoots people who try to kill her and doesn't wait to be rescued.
Brilliana and Olga, on the other hand, have no such limitations.
The Atoner: Miriam's mother, after Case Blue comes to pass; she poisons her own mother and seriously considers staying in Gruinmarkt when the USAF retaliates with nuclear carpet bombing. Her Clan bodyguard thinks otherwise, and drags her to New Britain just in time.
Blue and Orange Morality: The Families, having a medieval mentality, genuinely do not understand that if they detonate multiple nukes in Washington, D.C., what's left of the U.S. government will not open negotiations with them, but rather declare apocalyptic vendetta.
Changeling Fantasy: deconstructed harshly. Miriam is secretly a noblewoman with magical powers from a medieval-type world, and it sucks. Also in that Miriam's "adopted mother" turns out to be her real mother.
The Chessmaster: Patricia Thorold-Hjorth, Iris, Angbard, and a whole lot of others.
Conspiracy Redemption By the end of Book 5, the Clan's leadership is mostly in sane hands, and Iris has maneuvered Miriam onto the throne, so now the good guys can defend the Gruinmarkt against invasion.
Book 6 has the old bad guys come out of the woodwork for one last ride and get cut down completely. It also has Erasmus Burgeson begin to clean up his own world's revolution.
Convenient Miscarriage: Downplayed in that it isn't all that convenient. Nice for Miriam personally, not so much for politics.
Deliberate Values Dissonance: the people of the Gruinmarkt and New Britain don't think like modern Americans, and Miriam really doesn't like having to play by Gruinmarkt rules.
The Ditz: Olga is set up as this in the first book, but it's really a case of Obfuscating Stupidity. Kara, on the other hand, is a straight example.
Doom Magnet: Dear innocent bystanders, stay the hell out of range of Miriam (or the other plot lines for that matter) if you want to live. "Within range" means "on the same world."
The End of the World as We Know It: Gruinmarkt gets carpet-bombed with hydrogen bombs at the end of Book 6, and it's implied that the result is a global nuclear winter for the rest of that version of Earth.
External Combustion: Played straight with Mike Fleming in Book 5. He survives because the bomb is wired to the doors, not the ignition, and explodes before he gets too close to the car.
Feuding Families: there was even a civil war 30 years ago, and Miriam's return threatens to start it up again.
Full-Circle Revolution: explored and discussed by Erasmus, after he read the history books delivered by Miriam—particularly the histories of the French and Russian revolutions in Miriam's modern-day world. When the revolution does come about in Erasmus's world, Erasmus himself tries his best to clamp down on the security services to make sure that no analogue of Dzerzhinsky or Himmler comes to power. He nearly fails but for the intervention of the newly-fled Clan, which had its own bone to pick with the security directorate.
Gambit Pileup: by the third book, there are at least five different factions all either shooting at each other or inches away from doing so. This is Lampshaded when Miriam, in the second book, asks whether there's anyone in her entourage not working for the secret service. Her maid Kara responds, "Not me!"
Gambit Roulette: Iris has been running the whole plot from behind the scenes.
Genre Shift: It starts out exhibiting more fantasy tropes (noble families in Medieval Stasis; magical-seeming phenomena mediated through a Celtic-knotwork–style sigil), but by the midpoint the series is clearly economic and military science fiction. This is in part the result of Executive Meddling: one publisher already had an option on Stross's next SF novel, so he started this series as fantasy in order to be able to get it published by another company.
Giving Radio to the Romans: How Miriam gets rich in New Britain. By the end, with the Clan chased out of Gruinmarkt and resettled in New Britain, Miriam has decided—with the consensus of the leadership in general—that technology brokering will be how they'll support themselves.
This trope is Zig Zagged. They consider it, and ultimately everyone agrees to support if that's what she wants, which is surprising in the socially conservative culture of the Gruinmarkt. That's justified by both an inversion of Politically Correct History - people actually do understand the value of that kind of thing, because in that kind of culture it can prevent blood feuds and Death by Childbirth - and a possible Batman Gambit. In the end Miriam decides to keep it for political reasons. But then she has a Convenient Miscarriage, so it wouldn't matter. And then the Gruinmarkt is destroyed, so she wouldn't need her claim to power in their political structure anyway.
Incurable Cough of Death: We meet Erasmus suffering from tuberculosis, convinced that he'll soon die. Subverted in that Miriam's antibiotics ultimately save his life.
Invisible President—sort of. Although George Bush and Dick Cheney appear as characters on-page occasionally, their names are never used (except for on one page near the very end of Book 6 after both characters are dead), even though names of other public figures, such as Ashcroft and Scalia, are used more or less freely. The text, and all the other characters (even those for whom it makes no sense to do so), refer to the president and vice president by their supposed CIA code names, BOY WONDER and WARBUCKS.
This was vastly toned down in the 2012 editions. Cheney gets named a half-dozen times in volume 2, with almost three dozen namings in volume three.
Kissing Cousins: because the dimension-hopping is genetically recessive, the family is braided - people have to marry other clan members in order to ensure the children inherit it, but to avoid inbreeding, those family members can't be too closely related. There are a lot of second-cousin or first-cousin-once-removed marriages.
Medieval Stasis: thoroughly explained and explored in Gruinmarkt, and the new guard of Clan members want to drag Gruinmarkt out of the middle ages. They are opposed by older clan members and the hereditary nobility, which causes the friction of the story.
The Men in Black: the Family Trade Organization, which is set up somewhere around book three or four to investigate the world-hoppers and the threat they pose. Mike Fleming discovers in Book Five that WARBUCKS is the one pulling the strings, and is using it to destroy the evidence that he was involved with the Clan before his reentrance into politics.
Mighty Whitey: Miriam tries this, but her plans get repeatedly derailed because she gets caught in everyone else's byplay.
Misapplied Phlebotinum: A minor version is played straight at first, and a major part of the plot is ending that. The Clan has the ability to teleport between worlds, and they are using it to get rich by smuggling drugs past international boundaries and selling high-tech innovations to a low-tech setting. However, the system used at the start of the story is limited to what individuals can carry and it's unsafe to make trips more than once or twice a day, putting a sharp limit on the weight and volume of their interdimensional cargo. And trade is risky for cultural reasons (such as illegality) in both worlds. After Miriam throws a Spanner in the Works, people begin experimenting and work out ways to increase the amount carried, and she suggests that Giving Radio to the Romans would be a much higher-profit enterprise, given starter capital and a government that enforces patents.
Never Was This Universe: For the first couple books, the world Miriam grew up in could have been Real Life, the same world the reader is in, like numerous fantasy series that just happen to have a Masquerade. Eventually, though, there are offhand references to recent history playing out slightly differently.
Pirates Of Penzance: The general was the perfect model of a modern military man
Squee Executed and named hilariously in The Merchants' War. ("SQUUEEEEEEEE!")
Schizo Tech: The Clan create schizo tech wherever they go. In addition, New Britain has minor elements of it all by itself.
Science Cannot Comprehend Phlebotinum: Averted - the Clan firmly believe that their world-walking ability is a unique power that nobody else can duplicate, but given tissue samples from world-walkers, the American scientists succeed in reverse engineering the ability quite easily.
Spanner in the Works: Miriam's very existence knocks several conspiracies out of the water, and then she brings her reform plan into play.
Steam Punk: New Britain has elements of this, with zeppelins and trains being bigger and more important than they are now in real life, but planes never took off and cars are just becoming popular.
Teleport Interdiction - the antagonist in The Merchants' War strings ropes all over his castle to keep out the world-walkers.
Xanatos Speed Chess: Almost all of the many characters get caught up knee-deep in intrigue and hatch their own elaborate plans. Predictably, everything starts going to hell very fast, and that's just the beginning...