If I had to classify this book in any way, I would classify it as a dystopian thriller because the main character, Zed, travels from the future (in which there is a "perfect present" similar to that found in 1984) to modern day Washington D.C. in order to make sure that the perfect present is maintained. His job is to make sure that every sort of cataclysmic event occurs, including the imminent Great Cataclysm, so that his future (where there is no war, hunger or anything like that) is maintained. He must protect it at all costs, even if it means killing other people. He specifically targets Hags - or historical agitators - during his mission. The Hags also journey to contemporary time from the future to alter the past so that hatred etc. doesn't lead to so many deaths.
Besides Zed, who views his job almost as a surgeon would, there are a few other main characters: Tasha, a Washington based corporate lawyer that is beginning to question the morality of what she does; Leo, a former CIA spy; and Sari, a 22 year old Indonesian woman and illegal immigrant who is working for the South Korean ambassador and his North Korean wife. All of these characters cross paths in various ways - ways that would be credible in our every day lives and each interaction seems to carry increasing levels of danger.
I really enjoyed this book, so much so that I couldn't put it down and the 400 + pages flew by. I stole moments during my day to read it - breaks from my children, from the work that I brought home. I also really enjoyed the issues that were raised by this novel: America obviously considers itself to be in the perfect present and this novel took advantage of that. There was also the 9/11 paranoia that was imminently and obviously present, which overshadowed everything else. This book is NOT science fiction - while there are elements of time travel, it is more of a dystopic/critical look at contemporary American society then anything else. Definitely a must read,