This has exactly the sort of high-concept premise I like in Star Trek: infinitely many alternate universes, and a touch of time travel, that gives every character on the show a chance to display their problem-solving skills. There are, unfortunately, quite a few problems in its execution.

I liked the first three chapters of this book, where the premise is set up, and the last ten chapters, where it is resolved. Everything in between shows the Voyager crew solving the same problem in different universes. Not only is this boring, because we already know what's going on in chapter one (everyone's shifting between universes), but it's also repetitive, because we often see different versions of Voyager going through the same motions.

The blurb on the back of this book says Janeway is forced to work with Voyagers that have different agendas, but that never really comes up. There's a bit of frustration with the lack of communication, discomfort with meeting duplicate crewmembers, and the Voyager over the field of dead bodies is in a somewhat different situation than the Voyagers above an empty planet, or a planet full of people, but they're all on the same page about wanting to stop the shifts, and generally come up with the same solutions. On top of that, they reference the same Voyager episode ("Daedalus") over and over, and it does turn out to be relevant, as it turns out the events of that episode destroyed Voyager in every other universe, but it does get tiring and just makes me want to watch that episode.

The solution to the central crisis ends up involving every Voyager sacrificing itself by entering a subspace rift at the same time. It's shown that in every universe, B'Elanna discovers this solution and believes herself to be the only version of herself to have done so. The message being that all these alternate Voyagers have a shared scientific ingenuity, group cohesion, and value of the needs of the many over the one. It's a great finale, but it comes at the cost of the middle thirty or so chapters being a complete drag. In the process, it also resets the timeline so that the events of Echoes never really happened - this almost literal "reset button" being a classic trope in Voyager, if an unfortunate one.

Despite the problems, this was enough to get me hooked on the Star Trek literary universe, so expect more reviews of tie-in novels in the future.