Kudos to Welsh for some good research into Victorian Edinburgh and the medical profession, with only a few liberties with the facts (dates and such); I always love historical mysteries. My difficulty with this book was twofold: (1) Its unevenness in pacing. Some of the synopsis should be scenes, and vice versa; there is a lot of internal monologue and anxious cogitation; and the main plot line advances unevenly. (2) The psychological incoherence of the protagonist, Sarah. At times Sarah seems astute and "feisty," but her emotional states and loyalties shift from paragraph to paragraph. Trust turns to distrust on a dime; fierce energy flips to constitutional fatigue from having grown up in society; on one page she is so distraught she's retching up bile and on the next page (literally), she is taking a bath in lavender and giggling with her friend Elisabeth (who has just forgiven Sarah for mistakenly accusing her husband of consorting with prostitutes). The emotions felt overwrought to me and at times unwarranted. Sarah's haunting backstory seems to be inserted into the story merely to give her a "secret" for the reader to piece together rather than worked into the story organically, as an experience that shapes Sarah's motivations and behaviors. The author's 21st-century feminism appears at odd moments, and it felt at times that the author was trying to provide a (deserved) moral lesson vis-a-vis some of the characters: "So why turn on me?" I asked, exasperated. "We both had secrets, why persecute the one person who was in the same position? ... That's hardly sisterhood, Julia."
The book could also have used a bit more editing; the adverbs were at times overwhelming (e.g.: "I stared at him dumbly. I had forgotten that Elisabeth told me he and her husband were friends. Clearly, I thought bitterly, they had a lot in common") and repetitive: "Clearly looking after a houseful of mob-capped delinquents had its fair share of problems. Sergeant Lester and Miss Dawson were clearly acquainted, although quite how closely her blush only allowed me to speculate. He reassured us that his medical man was coming, clearly discomfited at Aunt Emily's unflappable demeanor."
But I have a feeling these are just the marks of a debut novel; I think Welsh could turn this into an engaging, interesting series, with a man/woman doctor-detective team, similar to some of Anne Perry's Monk mysteries.