3.5 stars, which ends up rounding up to 4 stars. 
 I went into this book not really knowing what to expect, as it hadn't been recommended by anyone. I liked the idea of family relationships and secrets, hoping it would be something like The Nest. It was similar, though it didn't draw me in quite as much as The Nest. I still enjoyed it, though, as the characters were interesting and the writing style was wry and entertaining. I liked the sister relationships. 
 I think Laurel was a very interesting character. I also liked the role that music played in this novel. The fact that the author didn't get into any overly mushy descriptions of the music was great-- it was a part of their life and its importance came through through the characters' behaviour, rather than saying something silly like "feeling the music pulsing through my veins" or something. 
 This book was great on audio. Gretchen Mol was an excellent narrator. I think I would recommend this book to people who enjoyed reading The Nest by Cynthia D'aprix Sweeney, due to the similar feeling. This is not a book that I find myself ranting and raving about, but it was a nice simple diversion which is what I needed now. 
 (view spoiler)[I was a bit confused by Sally's bipolar disorder. I didn't find that it really showed the classic symptoms, as there was more emphasis on the delusions about others and less delusions of grandeur, 
 impulsive behaviour, and such. I suppose the symptoms may have been different than textbook cases due to the fact that she was on mood stabilizers... also, this was not a medical book but a fictional novel so perhaps I'm overanalyzing it. I really appreciate when books accurately represent medical conditions, though, especially mental illnesses. Overall, my skepticism of Sally's symptoms did not take away from my enjoyment of the book. 
 Another spoiler: It was so creepy when Laurel's lies were unveiled! Ohhh yikes! I was worried she was going to kill the narrator or something but I suppose she was a scam artist, no necessarily a killer psychopath. I was surprised Mr. Clean turned out to be the random senile man, which was funny and a nice red herring from the author. I really thought it would be Laurel. (hide spoiler)]