Many time travel books are non-linear to some degree. But this book charts a whole new path when it comes to non-linearity. To be fair, the specifics of where are when are somewhat beside the point, but the places and times the characters go to have very few recognizable features, which leaves the reading without a hook on which to make sense of the narrative (if it can be called that). It's kind of like reading abstract art. Like abstract art, a very few things come into focus by the end if you stare at them long enough, but it requires way too much effort. If you like that kind of thing, carry on, but it's really not for me. And yes, I already know I'm a philistine when it comes to art.