The Family Trade by Charles Stross
This is the first book of the Merchant Princes series (got the first four books in the series at a sale at Katy Budget Books). The series combines the idea of parallel worlds with severe economics; each of the worlds are at a different stage of economic development, and our protagonist is determined to take advantage of this as a wealth creation mechanism.
Miriam Beckstein is a reporter on the trail of a huge story about drug smuggling. She and her investigative helper, Paulette, get fired upon presenting their story to management. In a funk, Miriam goes to see her foster mother, who sees this as a good time to give her a box of things from her “real mother”. This box includes a locket, which when opened shows a braid design that enables those of a particular bloodline to “world walk”.
Miriam finds herself in the same physical place, but in a world that is stuck in the medevil times, with a powerful ruling society that includes the Clan of world walkers. She is acutally a logn lost duchess of the Clan, named Helge whose mother Patricia and father were killed in blood feud between warring families in the Clan (there are six families). Miriam finds that the Clan’s main money making scheme is sending messages (by moving in our modern world and transporting back to the medevil world) and smuggling drugs.
As a long lost Duchess, the Clan tries to control her, and some try to assasinate her, as she would now reclaim shares of the Clan that belonged to others before her return.
She meets a kindred spirit in Roland, who was educated in our world, but is considered a rebel in his own. As she learns that she has some power as a Duchess and a world-walker, she starts to form her own plans for either escaping, or showing them her value through breaking into new businesses that could use world-walking.
The novel is incomplete, it ends in the middle of a story, heading directly into the second book, The Hidden Family. But Miriam is an engaging character, she doesn’t roll over when confronted by all of these challenges. And though the “how” of world-walking is never explained, the mix of economics, politics and parallel worlds makes this an enjoyable series, one I hope to read straight thru.