The Complete Maus

One of the most powerful books (graphic novel, or otherwise) that I've ever read. It's a gripping look at the struggle and survival of the authors parents during their stay at the concentration camps during WW2.

The illustrations are also masterful, I recommend watching this short video essay on the amount of detail and thought that goes into the layout of each page - https://www.youtube.com/watch?v=1dQEfL2BfUM