Totally amazing. Rachel is a female in London who just got divorced. One day she sees something while she is on the train that is shocking and the story goes from there. 
 The critics are hailing this as the next "Gone Girl" and I have to say I like the ending and story line of this book so much more than Gone Girl. So I highly recommend this book if you did not like "Gone Girl". If you don't like thrillers, this is not the book for you. 
 I highly recommend this book though.