Oh, my goodness, this book seemed interminable. I stuck with it just so I could finish the thing. I'd already invested so much time, I couldn't see just putting it down unfinished. Interesting premise and moving enough at the beginning, but man, the plot really got weighted down with all the rather unnecessary twists and turns. And I really felt like the author was just hammering and hammering the "secret of the second twin" thing a little too hard. The emotions expressed by the characters seemed forced; they were amazingly self-reflective for people who were supposedly living a perpetual lie. 
 And then there were the annoying little details. First, the edition I had really needed a better copy editor. For at least the first 2/3 of the book, there was a missing word or a repeated word or phrase practically every other page. Really very distracting. Then there were the details that the author didn't get quite right. One character looked out the window at a robin at a feeder. Unless that feeder was filled with grubs and worms, a robin would not have been there. An episiotomy is done with scissors not with a scalpel, and the area of southern Ohio near the Ohio River is the foothills, not flat fields as the author describes them. 
 I think if the plot had moved along better and the characters had acted in a more believable manner, I could have overlooked the little piddling inaccuracies. As it was, they stood out like crazy because I just wasn't drawn in by the story.