The Long War: The Shaking Up of The Long Earth
I quite liked Pratchett and Baxter's previous collaboration, "The Long Earth," which revolved around humanity discovering that they could access an infinite number of alternate Earths, each different from each other. "The Long War" is a sequel to this story, taking place roughly 10 years after the ending of the previous book. Humanity is getting increasingly comfortable settling the Long Earth, with communities popping up revolving around all-new and all-different ways of life. However, there are problems: the governments of many nations on the Datum--the original Earth where humanity lives-- are becoming increasingly hostile to the Long Earth and the people who reside there, who themselves are growing independent and finding that they don't need Datum governments any more. In addition, isolated incidences of humanity's abuse of the trolls--the peaceful naturally stepping hominids who are omnipresent across the Long Earth--is causing the trolls to vanish, worrying those who believe the trolls are fundamental to the Long Earth functioning. And there may be even more sapient species on alternate Earths, who view humanity with suspicion and hostility. And in the background, there have been literal rumblings across multiple worlds, including the Datum, from Yellowstone....
This book has both the good and bad traits of its predecessor. The good: it is incredibly inventive, with each Earth being significantly different from another, and features now multiple races of sapient but not humanlike creatures. The bad: it hares off in a million directions at once, making it seem unfocused and confusing, with the occasionally extremely abrupt end. I also must say that I did not like the way the book seemed to repeat the final climax of its previous book, albeit on a much larger scale.
Joshua Valiente is as always an interesting protagonist. Now a family man with a wife and son, at the beginning of the book he had settle down to being mayor of a tiny town on one of the stepwise Earths. But when the mysterious Sally Linsay shows up with a mission for him, he finds himself compelled to go with her. He is determined, good-natured, and quite selflessly brave. Other protagonists, including the retired police officer Monica Jansson, former priest Nelson Akiziwe, captain of a military blimp Maggie Kauffman, and many others, each seem distinct characters, and I found myself liking all of the different plot threads (although the amount of different plot threads was a little overwhelming, as I've mentioned).
All in all, I found that I liked this book, although it did have some issues. If you're a fan of either Pratchett or Baxter (whose books I still haven't read), or if you liked the first book in the series, it's definitely worth checking out.