The Hidden Family

the long version

Miriam, a hip tech journalist from Boston, discovered her alternate world relatives in The Family Trade, and with them an elite identity she didn't know was hers. Now, in order to avoid a slippery slope down to an unmarked grave, Miriam, known as Lady Helge to the Family, starts applying modern business practices and scientific knowledge to a trade dominated by mercantilists -- with unexpected consequences for three different timelines, including the quasi-Victorian one exploited by the hidden family. Charles Stross is one of the big new SF writers of the 21st century, and the saga of The Merchant Princes is his most ambitious work yet.