DMZ is a Vertigo book, and while it's technically speculative fiction, it isn't the usual kind of fantasy or SF you usually find from Vertigo. Instead, it's a gritty but very human story about the no-man's-land in the next war: Manhattan.
The premise is spelled out quite lazily over the first two collections -- one characteristic of the book is that, while it seems to be a thoroughly designed world, it only tells you bits as they become relevant. Indeed, after reading volume two, it still isn't terribly clear why the new American civil war started. Ultimately, the reasons don't matter all that much to the people on the ground in the DMZ. What is clear is that, in the post-Iraq battle between the American Free States and the USA, the battle lines stalled at New York, with Manhattan as the ultimate in urban warfare. One side is in NJ, the other in CT, and the folks in Manhattan are just trying to get by, a year after a botched evacuation left a third of the population behind.
Our protagonist, Matty Roth, is a young photojournalist who was flown into the DMZ to take the pictures for a Big Name Reporter. Moments into the assignment, everything goes to hell and Matty finds himself alone, knowing little about the situation aside from the propaganda that the US networks have been telling him. What he finds is a far more complex environment than he ever expected: an island of a half-million people trying to survive. It's a war zone, and you can never forget that, but it's also a living city full of people who are proud of their land and damned if they are going to abandon it.
In the end, Matty decides to stay and report from the inside on what's going on, and that's the general premise of the story. But things are never quite that simple, of course -- as the only full-time reporter in the middle of a war that is as much about propaganda as anything, he sometimes finds himself a key player in the larger war, despite having little idea of what's really going on. In particular, much of Volume 2 is about what happens when the Free States and US both realize what a useful pawn Matty could be for them, and the difficulty of holding onto both his honor and his life when that happens.
Mostly, though, this is the story of a strange new world. With all the old assumptions called into question, New York has fractured along many lines, with each neighborhood developing its own odd character. Whether it's Chinatown (now tightly controlled and off-limits to non-Asians), Central Park (full of mysterious "ghosts" with their own agenda), or the river side of the island (largely abandoned due to snipers), each issue is its own bit of education for Matty and the reader.
This is really fine pure speculation. The writer, Brian Wood, has thought the scenario through in depth, and much of what he says rings very true. While this is very much the tale of New York turned into Baghdad, it is not a story of grinding poverty or despair. Most of the major characters are the people who are trying to make a go of it. So amid the bullets, we get moments of Matty being introduced to the good eateries that are springing up (mostly vegans growing their own crops on the rooftops), the music and books still being played and written, and especially the many different kinds of people he encounters along the way.
Highly recommended. The story is a bit dark, but never oppressive. The characters are well-thought-through, and the main arc of the series is classic, as Matty slowly grows from being a self-absorbed twit into a significant member of this new community that is developing. The art matches the story well, making yet another great series from Vertigo. Check it out...