The Killing Joke captures the essence of a well-written Batman book. From beginning to end, it is a dark read - very dark in some places, somewhat lightened in others, but without question a story of tragedies and a twisted mind.
Alan Moore, Brian Bolland, and John Higgins each did an excellent job in telling this story. Moore's setup of the story is superb - the way he begins and ends the story in an identical manner shows that the end is just a new beginning (Moore also used this technique in Watchmen - I haven't read enough of his work to know if uses this method in each of his stories, or just some). His dialogue shows the essence of each character, boiled down into one or two lines, especially with Commissioner Gordon. Right after the Joker has torn Gordon's life to shreds, Gordon tells Batman, "I want him brought in ... and I want him brought in by the book!" To the core, Gordon represents the law and justice.
The illustrations and coloring are perfect for this book. The way Higgins uses color captures every emotion in the book - especially madness. Bolland's illustrations are excellent - the wordless panels and pages are some of the most powerful scenes in the book, especially between Barbara Gordon and the Joker. The man can also draw a fine Batmobile.
This is a book every Batman fan should read - both because of the reasons listed above, and because of the pivotal moment in Barbara Gordon's life that would impact every future Batman comic book. It is not my favorite Batman graphic novel, but it is a definite must read.