The Merchant Princes

The Merchant Princes is a science fantasy and alternate history series of nine novels by British writer Charles Stross. In the series, there exist a number of parallel worlds, all of which are on the same geographical Earth but with different societies at different points of development. Members of a certain bloodline can travel between these worlds along with their immediate possessions. The series largely follows Miriam Beckstein, a technology journalist raised in a familiar "normal" Earth, who discovers she was born in a parallel world and is a member of this bloodline. She quickly becomes entangled in political maneuvering and assassination plots with her estranged family. Miriam uses modern technology and investigative journalism to attempt to stay a step ahead.