This is a fine mix of Big Idea SF with human drama on a much smaller scale. The Big Idea is a conqueror from the future named "Kuin" who is somehow able to send massive monuments to his victories back in time, where they stand invulnerable and ominous over the lands he is destined to conquer. The first ones are in Thailand, but over the next few years they appear all over Asia. Some materialize in relatively unpopulated areas, but some appear in the middle of cities, flattening them with shockwaves. Scientists determine (using hand-wavey physics) that these "chronoliths" are indeed from the future, which means Kuin really is going to conquer all of Asia in about twenty years. This sets off global turmoil. Some prepare to fight; others begin urging accommodation or outright capitulation. By the time Kuin's chronoliths are appearing outside of Asia, there are entire "Kuinist" militias and organizations, and of course innumerable warlords in the now-devastated Asian warring states claiming to be Kuin.
This is the backdrop of the story, which is really about Scott Warden and his family. Scott is a kind of mediocre husband and father slacking off in Thailand when the first chronolith appears there. Being one of the first witnesses to the first appearance of the chronoliths inescapably binds him to the events that follow over the next few decades. As he is told by Sulasmith Chopra, the scientist who studies the chronoliths and believes that Kuin can be stopped, "there are no coincidences." Scott goes through a divorce, his ex-wife marries a Kuin accommodationist, his daughter, as a teenager, hooks up with a young Kuinist ideologue who turns out to be a psychopath, which brings Scott together with the psychopath's mother. His drug-dealing friend from his time in Thailand reappears, as do all the other characters we meet over the course of the book.
It's Scott's interactions with his family and friends that are the heart and soul of this book. The characters are not all vivid or interesting, but they are distinct and they each have a purpose in the story, and Scott narrates a compelling story as he weathers a long, brutal economic downturn that turns even the U.S. into an impoverished country, works for Sulasmith Chopra trying to understand who Kuin is and what the chronoliths represent, travels to Mexico to save his daughter from Kuinists who have gone on a "haj" to see the manifestation of the first chronolith in North America, and finally, goes to meet his destiny in a climactic confrontation in Wyoming.
"Kuin" is basically a MacGuffin; ultimately, it doesn't really matter who he is or if he even exists. It's what he represents that drives all the world events. With the rules of time travel Wilson establishes in this book, cause and effect are looped together, so we are finally able to understand why all the small human dramas Scott was involved in add up to something of greater significance at the end. Wilson's take on time travel is intelligent and subtle, and by keeping Kuin a mysterious off-screen presence whose very existence remains in doubt, he makes the whole thing plausible without having to deal with paradoxes, parallel universes, and the like. Wilson has thought through all the implications, and if the end of the story seems like a bit of an anti-climax, it's also one that makes perfect sense.
Wilson's writing is straightforward but occasionally he waxes almost poetic. He's one of those writers who likes to show off his vocabulary, yet even the tech and time travel physics infodumps were brief and clear.
Although this wasn't the most wonderful book in recent memory or a true masterpiece, it's definitely a hidden gem of high quality, and I came very close to giving it 5 stars. Given the eloquent but clear writing, it's a science fiction novel that a non-sci-fi fan might well enjoy, since the time travel and near-future history is only background for the characters and the plot which drive the story. I give it 4.5 stars; it's very good, I just didn't quite find it unique or mindblowing or the characters memorable enough to make it awesome.