This just borrowed too much from previous writings for me. It's simular to H.G. Wells The Time Machine and the plot is also akin to the author's best work The Forever War. Beware, spoilers ahead....there are a few nice twists here. The user can go only forward, in increasing amounts of years and he doesn't return to where he started out from. At first, this works pretty well. He gets into awkward situations and manages to get out of them by activating the time machine and making another jump. But this story contains a lot of unanswered questions, characters were used that made me wonder why they had to be there in the first place and then in the last third or so the book fell flat. The story started to rely on trite dialogue between shallow characters and at that point I felt it couldn't end fast enough. A good enough read for Haldeman fans but for everyone else if you're looking for a time travel story there are better ones available.