I won't spoil the book for those who haven't read it. I really liked the characterization in the book. Rachel, the main character, was very fascinating to me. Rachel suffered from depression and was an alcoholic and I don't think I've ever read a more realistic portrayal of someone with those issues before. I spent most of the book switching between dislike and pity for Rachel. You really felt bad for her sometimes. When she couldn't get out of bed or cook herself a meal or stop drinking I just wanted to reach into the book and shake her by the shoulders and help her somehow.
It's a sign of a good writer when the characters you're presented with have multiple layers to them and are not always likable. It's realistic. Rachel was battered down and pathetic and broken. They're not just another cookie cut out of a typical book character. You keep wanting to turn the pages because you have so many questions. You become invested in their lives and want things both good and bad to happen to them. They become real.
Another thing I liked about this book was how the plot wasn't linear. It takes a lot of skill to structure a plot that is not a straight line. The typical beginning-middle-and end is the easy route to take and I don't judge writers for taking it. If you can master the more difficult road of the non-linear plot you're going to get a nod of respect from me. You put in the extra work and did something different. Good for you.
I also liked how this book highlighted domestic abuse against men. This is RARE. It certainly added some spice to the plot. It made you question things and just pulled me in further. Very well done.
The Girl on the Train had a strong Gone Girl vibe to it. I highly recommend it to anyone who likes a mystery and something a little bit different. A movie based on the book is coming out soon. I will definitely be going to see it.