I first read this book not long after it came out. WOW! Maus was the first real deal, big time graphic novel. It was a nonfiction story of the author's parents' experience in the Holocaust. The author, who is also the illustrator, chose to use animals to portray the different groups: mice are Jews, cats are the Nazis, etc..
I used this graphic novel with 7th - 12th grade students one year when we studied the Holocaust. It does an unbelievable job of showing what that horrific time was like for the author's father and mother. But, it does something else... the novel flip-flops back and forth between current time and the time of the Holocaust. This let's the reader see that many survivor's carried scars from that time that never left them; scars that made brought that time long past upon their children.
Spiegelman takes you into hiding with his father, into the camps with his mother, and shows you the trauma that extended far beyond that time.