The Hidden Family by Charles Stross
This is the second book of the Merchant Princes series (got the first four books in the series at a sale at Katy Budget Books). It is very much a straight continuation (i.e., no cliff hanger) from the 1st book, The Family Trade.
Miriam, fresh off several assassination attempts, is back in our world, bringing along Brill from the Clan’s home world (for background, from the first book, Miriam and others with similar DNA can world-walk by looking at a particular braid design; her family in world 2 is called the Clan, made up of six families; world 2 is about 150 years behind our world in development, and has a monarchy and hierarchical caste system). From one of the assassination attempts, she retrieved a locket from one of the assassins (whom Miriam killed); the locket contains a braid, but of a different design. She cannot use it to world walk from our world, but she can from world 2, and it takes her to…world 3, which is more advanced than world 2 (airships, primitve cars) but not as advanced as ours.
The Clan is still aprehensive of Miriam, and may try to find her incompetent, taking her money and her power. To thwart this, she decides to set up a business in world 3, importing patents and ideas from her world, to show the Clan that a new way of business will work and to give her more power and leverage against those in the Clan who would use her or put her aside. She is not sure who to trust, except for her foster-Mother (Iris), her partner/legal advisor (Paulette), and Brill, who she brought from world 2. She does not trust Roland, her lover from world 2.
The rest of the novel is a study in economics and political subterfuge – the ecnomics of trying to show the world walkers a different way to make money other than carrying messages and smuggling drugs (i.e., transferring knowledge), and the political issues of finding the Hidden Family that created the different braid (apparently by accident, finding world 3 by accident), finding a traitor in world 2, and avoiding the government and authorities in all three worlds.
The series is complex, including the Clan and the hierarchy in world 2; the governments of New Britain in world 3 (there is no US and France has taken over the continent of Great Britain in world 3) and the plethora of characters. But it is a fun read…I’m not sure if I could keep it all straight if I was not reading them straight through.