Maus, A Survivor's Tale by Art Spiegelman
Together Maus I and Maus II are both the story of a Holocaust survivor and the story of a writer/artist trying to tell that story.
I'd read the books years ago as a young adult (probably 2 or 3 years after they were first published) and I remembered them, but only vaguely. One of the things I did not remember was the dynamic between Artie and his father. I think in some ways it must have been just as hard for Spiegelman to be honest about his relationship with his father as it was to tell his father's story.
Another thing I didn't remember was how Spiegelman portrayed the other nationalities in the book. I remembered the cats and mice, but not the Poles as pigs, Americans as dogs, etc.
The books are poignant and what strikes me the most about them is how honest they are. Honest about the Holocaust and all its atrocities, honest about the father and son relationship, and honest about the author and his own failings.