You by Caroline Kepnes (2014)

Well-written thriller about a bookstore clerk who stalks, romances and stalks an attractive female customer. The stakes are high, and the perspective is really interesting. Although I normally loathe book written in the second person--to "you"--writing this narrative to the stalkee works beautifully and is very chilling. 

It's fascinating to read a stalkerish tale that takes place in the contemporary social media landscape. It's a deeply complex and yet very readable story. 

To say more would be spoilery.