Will Eisner would argue his Contract with God was first.
Though there were other books before that.
Ronin certainly was an earlier one. I have a worn copy I got used, and I remember enjoying it. I am a bit curious if he still has it, though the new Miller stuff seems to be really short on substance and one trick on style. Though art wise, this looks like an improvement!
Still - Dark Knight Returns will always be in my top 5.
