Robert Kirkman's comic book series The Walking Dead has managed to inspire one of the most popular shows on cable TV at the moment, and the book itself doesn't show any signs of stopping, having just passed the 100 issue mark a few months back.
Much like the TV show, the comic book is chiefly the story of Rick Grimes, a police officer who awakes from a gun-shot induced coma to find that his family is gone and his home town has become overrun with zombies. Rick sets out on a quest to find his wife and son, and along the way becomes the de facto leader of a small group of survivors. As the series progresses, the burden of leadership and the constant horror he's forced to confront hardens Rick to the point where his only purpose is to safeguard the people he loves, and nothing's going to stand in his way, living or dead.
Like much of Kirkman's work, one of the strengths of The Walking Dead is the sense that anything can happen; at this point I've read up through #96 of the series, and very few of the original characters are still standing, and those that are have not emerged from their traumas unscathed. Every time it feels like Rick's crew has finally found a place to be, if not happy, at least safe and content, as the reader you are always waiting for the other shoe to drop. At times that sense of foreboding can drag the book down for me, as the constant misery is wearying, but since the most recent home for the group has been in place for over 30 issues, it has given me enough breathing room to be ready for the next big tragedy -- which by all accounts takes place in issue #100.
While not a perfect series -- the decision to have one of the series strongest women characters by repeatedly raped and humiliated by a villain was a definite low point for me -- The Walking Dead still manages to keep me coming back volume after volume.