The Girl on the Train : A Novel by Paula Hawkins (2015, Hardcover).

I found this on my bookshelf it was given to me as a gift and I never read it.

Inside the book on the desk cover flap:

Every day the same way just takes the same commuter train every morning and night. Every day she rattles down the track, flashes pass a stress of coded suburban homes, and stops at the signal that allows her to daily watch the same cup of breakfasting on their deck. She looks forward to it. She even started to feel like she knows them. Jess and Jason she calls them the life as she sees it it’s perfect not unlike the life she recently lost until today and then she sees something shocking it’s only a minute until the train moves on, but it’s enough. Now everything’s changed unable to keep it to herself, Rachel goes to the police. But is she really as unreliable as they say? Soon she is deeply entangled not only in the investigation but in the lives of everyone involved. Has he done more the harm than good?