I found the review that says the plot is slow and that Sarah Waters uses too many words where few would suffice astounding. I found this novel one of the most unputdownable I have ever had the pleasure to read and cannot imagine a more inappropriate criticism. It is such a fast-paced and brilliantly plotted book, with, in my opinion, not a single wasted word. The descriptions of the day-to-day life of the country mansion and the make-up of the asylum were fascinating and perfectly done, certainly not overdescriptive in the way in which Dickens sometimes indulged. Not only was it wonderfully gripping, but a serious read in content and a stylistic work of art. The dialogue and narratives are genuine and alive, drawing you into the intriguing world of the characters. The skill of the author, in constructing a work of such perfectly balanced symmetry of plot and depth of atmosphere and subject, blew me away. I think it is a work of genius.