I haven't read this novel, but I wanted to add to user wingertjd's comment. Batman: the Killing Joke originally was a highly acclaimed 1988 graphic novel written by Alan Moore and illustrated by Brian Bolland. The Gwinnett Public Library has it and I highly recommend it. An animated film version of it was later developed, and that's probably the "cartoon" described by user wingertjd. The film itself was not as widely acclaimed as the graphic novel, so start with the graphic novel first!