This biographical graphic novel by artist/writer Art Speigelman is essentially a story about the Jewish Holocaust, but with the curious twist that Speigelman draws all the characters as different kinds of animals according (loosely) to their race. Jews are mice, Germans are cats, Poles are pigs, and Americans for some reason are dogs. So right off the bat (so to speak; there are no bats in the story) the book kind of captures your attention, even if the author never really goes far with the idea as a literary device.
Instead, the value of the book is with the story, which flips between modern day scenes where Speigelman visits his elderly father Vladek in order to interview him about the Holocaust, and flashbacks showing what Vladek describes. Almost as much time in the latter is given to describe the buildup of the travesties so that we get to see the gradual decline of Vladek's wealthy Polish Jewish family and its ensnarement in the Nazi machine.
Interestingly, I actually got more enjoyment out of the parts of the book showing the interactions between modern Vladek and his aspiring biographer of a son, which included lots of little dramas, challenges, and caricatures. It was neat to see how the elderly Vladek honestly wasn't that likable a fellow --he's miserly, manipulative, controlling, and unfair to his son-- and how that contrasted with the heroic, loyal, loving, and resourceful Vladek from the flashback scenes. The interesting (some might say "artistic") thing is that even though these discrepancies exist, you can still see how it's the same character and how the hardships of the earlier times acted to define the man we see in his elder years, both for good and bad. Art Speigelman himself also makes for an interesting character study, as he's not without his own issues.
About the only major complaint I have about the book is that the way Speigelman draws the characters doesn't allow him to do much to differentiate between them much. There were many scenes where I lost track of who was who because the panels just showed a bunch of identical looking animals. But otherwise the book's stark black and white art style works given the bleak subject matter.
Sometimes it's hard to recommend a Holocaust book --it's not the most cheerful of subjects and yet has been extensively covered in other works. But Maus works pretty well for how it blends modern and past characters as well as its inclusion of a wider time frame. Check it out.