In the Garden of Iden by Kage Baker
This is the first of Kage Baker’s novels about Dr. Zeus Incorporated, otherwise knows as the Company, an organization that recruits time travelers to track lost bits of history and preserve them for future discovery—and profit. The problem is that the Company has grown so powerful that nobody seems to know who’s running it or to what ends.
Garden of Iden tells the story of Company operative Mendoza: her recruitment as a small child, where she faced certain death at the hands of the Spanish Inquisition in 16th Century Spain; her training and augmentation by the Company, which transforms its operatives into immortal cyborgs; and her first assignment among the mortal humans she has come to disdain and fear.
But once arrived in Renaissance England to collect long-extinct plants, Mendoza finds that the 16th Century is worse than she remembers and better than she imagined. Baker is a better writer than I thought at first, because I was two-thirds of the way through Garden of Iden before realizing I’d been sucked into a romance novel. But by that time I was past caring. Interesting characters, rich historical settings and a plot which hinges on a highly entertaining science fiction/time travel premise make Garden of Iden a winner.