Come Closer - Sara Gran

I don't usually read books in the horror genre, but I picked this up after it was mentioned in the NY Times Book Review. This slim volume can be finished in one sitting, and makes for an entertaining couple of hours.

Amanda works for an architectural firm, and is contentedly (if not blissfully) married to her husband Edward. Her career and marriage unravel as she begins having dark thoughts and acting out hurtful behaviors that she becomes unable to control. Come Closer is unique because it is written in the first person, so it is not clear to the reader whether she is becoming mentally unstable or if she is truly possessed by a demon.

This book is not gory or make you sleep with the light on scary, but it is very creepy ad readable.
Come Closer: A Novel - Amazon info page