What must it feel like to have pieces of one's life erased from the time line as if they never were? If someone still remembers a changed event, then did it still happen?
Many modern time-travel stories ask questions like this, but few seek to present a plausible answer. I have lost count of the number of books/movies I have come across which begin with a fascinating time-travel premise, but then degenerate into an ordinary action/thriller/mystery/horror story which simply uses some variant of the grandfather paradox/alternate timeline/parallel universe concept as a plot device.
This book is different, in that it takes time-travel more seriously; making it an integral part of the plot and presenting an overarching view of how it would actually work if it became possible. That is not to say that the novel is a dry treatise on the subject, far from it, it is bound up with a very human story of invention, discovery, friendship, and sacrifice.
When we first meet him, Z-4Q (pronounced Zaq) is a timeline correction operative, an agent who is sent backwards and forwards in time to police the timeline. In order to combat time sickness, a disorientative condition which afflicts those who time-travel regularly, agents' memories are routinely erased between missions. There is, however, an unfortunate side-effect in that they eventually lose all but a few traces of the rest of their memories. As the story unfolds, however, we find that this is but a snapshot from Zaq's personal timeline…
Be warned, though, the timeline of the story is complex, and it is best to pay attention to the time stamps at the head of each chapter. That said, this is a well written, absorbing tale, and will appeal particularly to those fascinated by the complexities of time-travel and the effect it could have on the world around us.