From the Comic:
Batman: "Hello. I came to talk. I've been thinking lately. About you and me. About what's going to happen to us, in the end. We're going to kill each other, aren't we? Perhaps you'll kill me. Perhaps I'll kill you. Perhaps sooner. Perhaps later. I just wanted you to know that I'd made a genuine attempt to talk things over and avert that outcome. Just once. Are you listening to me? It's life and death I'm discussing here. Maybe my death... maybe yours. I don't fully understand why ours should be such a fatal relationship, but I don't want your murder on my... hands..."
Joker: "Memories can be vile. Repulsive little brutes, like children I suppose. But can we live without them? Memories are what our reason is based upon. If we can't face them, we deny reason itself! Although, why not? We aren't contractually tied down to rationality. There is no sanity clause. So when you find yourself locked down in an unpleasant train of thought, heading for the places in your past where the screaming is unbearable, remember: There's always madness. You can just step outside and close the door, and all those dreadful things that happened, you can lock them away. Madness... is an emergency exit."
Joker: "So... I see you received the free ticket I sent you. I'm glad. I did so want you to be here. You see, it doesn't matter if you catch me and send me back to the asylum... Gordon's been driven mad. I've proved my point. I've demonstrated there's no difference between me and everyone else! All it takes is one bad day to reduce the sanest man alive to lunacy. That's how far the world is from where I am. Just one bad day.
You had a bad day once, am I right? I know I am. I can tell. You had a bad day and everything changed. Why else would you dress up like a flying rat? You had a bad day, and it drove you as crazy as everybody else... only you won't admit it! You have to keep pretending that life makes sense, that there's some point to all this struggling! God, you make me want to puke.
I mean, what is it with you? What made you what you are? Girlfriend killed by the mob, maybe? Brother carved up by some mugger? Something like that, I bet. Something like that...
Something like that happened to me, you know. I... I'm not exactly sure what it was. Sometimes I remember it one way, sometimes another... if I'm going to have a past, I prefer it to be multiple choice!
But my point is... my point is, I went crazy. When I saw what a black, awful joke the world was, I went crazy as a coot! I admit it! Why can't you? I mean, you're not unintelligent! You must see the reality of the situation. Do you know how many times we've come close to World War Three over a flock of geese on a computer screen? Do you know what triggered the last World War? An argument over how many telegraph poles Germany owed its war debt creditors! Telegraph poles!
It's all a joke! Everything everybody ever valued or struggled for... it's all a monstrous, demented gag! So why can't you see the funny side?
Why aren't you laughing?"
Batman: "I spoke to Commissioner Gordon before I came in here. He's fine. Despite all your sick, vicious little games, he's as sane as he ever was! So maybe ordinary people don't always crack. Maybe there isn't any need to crawl under a rock with all the other slimey things when trouble hits. Maybe it was just you, all the time!"
Batman: "Don't you understand? I don't want to hurt you. I don't want either of us to end up killing the other. But we're both running out of alternatives... and we both know it. Maybe it all hinges on tonight. Maybe this is our last chance to sort this bloody mess out. If you don't take it, then we're both locked onto a suicide course. Both of us. To the death. It doesn't have to end like that. I don't know what it was that bent your life out of shape, but who knows? Maybe I've been there too. Maybe I can help. We could work together. I could rehabilitate you. You needn't be out there on the edge anymore. You needn't be alone. We don't have to kill each other. What do you say?"
Joker: "No. I'm sorry, but... no. It's too late for that. Far too late. Hahaha. You know, it's funny. This situation. It reminds me of a joke..."
Joker: "See, there were these two guys in a lunatic asylum. And one night, they decide they don't like living in the asylum anymore. They decide they're going to escape! So, like, they get up onto the roof, and there, just across this narrow gap, they see the rooftops of the town, stretching away into the moonlight. Stretching away to freedom. Now, the first guy, he jumps right across with no problem. But his friend, his friend daren't make the leap. Y'see... y'see, he's afraid of falling. So then the first guy has an idea... He says, 'Hey, I have a flashlight with me! I'll shine it across the gap between the buildings. You can walk across the beam and join me!' But the second guy just shakes his head. He suh-says... he says 'Wh-what do you think I am? Crazy? You'd turn it off when I was halfway across!'"
About the Comic:
Amongst my own work, The Killing Joke...Yeah, there's loads of emotion layered on there. It's quite clever. The plot works, on a material level. But it's not about anything, it's not about anything of human importance, it's about Batman and The Joker and you're never gonna meet anybody like Batman and The Joker. It's of no use to you as a human being. It's one of the works – there's some very good things about it, but it's lacking something, and it's lacking soul. It's not got the thematic drive that say Watchmen has, which I was doing at the same time. That was my big mistake...I was doing The Killing Joke at the same time as I was doing Watchmen.
Well, psychotic murders — the key word there is “psychotic,” which is, as far as I know, an illness. This is not to say that people shouldn’t be entitled to feel rage or the lust for revenge when something happens to them at the hands of somebody like this, but you’ve got to remember at the end of the day it’s not strictly speaking that person’s fault. That something has happened to them, they have made some bad decision in their life, and while all of us are responsible for our actions, sometimes people get broken and it is increasingly difficult for them to know their own actions. So I suppose that if there was anything actually being said in “The Killing Joke,” it was that everybody has probably got a reason for being where they are, even the most monstrous of us.
"[ The Joker has ] a kind of muddy kind of origin. They’d said that he’d been the leader of a criminal gang called the Red Hood Mob and that while trying to escape from Batman he’d swum across this river of chemicals...That was about it and this was from a story from, like, the late ’50s or something and so I thought “Okay, I won’t contradict that,” because I kind of believe in working by the rules of the material as it already exists but I can put a lot of spin on that."