For the most part I enjoyed this story. I've always liked Sherlock Holmes, and this story did a credible job of creating a new story surrounding the legendary detective. The medical aspects of the mystery intrigued me as well. Anna's struggles to practice medicine and keep others from discovering she's a woman seemed well thought out.
My only quibbles are that for someone who prided herself on presenting a purely professional appearance, Anna had a few too many very emotional outbursts. I'm also about as romantic as a rock, so the attraction between Anna and Holmes left me cold. The last part of the story with the fake fight in the carriage struck me as especially cheesy.
These issues aside, I would rate the book a 3.5, and I will be reading additional books in the series.