I AM LEGEND BY RICHARD MATHESON - HORROR/DYSTOPIAN -
What if the night really was dark and full of terrors?
There are very few novels that give you a genuine feeling of unquiet. I remember reading Dracula and having this feeling. "I AM LEGEND" evokes a very similar response, and hits all the right notes in regards to exploring humanity's breaking point.
The protagonist slowly fractures over time in an upset world. And he struggles with his own sanity, depression, and loneliness.
Saddest of all is the protagonist's relationship with his once neighbour, now walking deceased. The obsession grows and festers.
Without saying much more about the story, "I AM LEGEND" is a vital read. It raises many questions, and denies the reader a satisfying ending.