The Goodreads hivemind is right, the second book is better.
Earth is in preparation mode, readying to meet the Trisolaran fleet 350 years in the future. Luo Ji, a could’ve been cosmic sociologist, is elected Wallfacer: a strategist tasked with outwitting the Trisolarians.
The book meanders for its first third. Three retired men talk politics. Luo imminent-domains a mansion and gets a mail-order bride. The “Wallbreakers” do nothing but take orders within the Three Body Problem.
But the slow windup is tolerable given the world’s pressure-cooker atmosphere. The issue’s scale matches global warming but includes a countdown to annihilation (each chapter starts with the current year within the ‘Crisis Age’). There’s mass confusion and pessimism. Factions of humans continue to debate welcoming the aliens, negotiating with them from space or continuing with plans for war.
The book takes a quantum leap when Luo hibernates smack dab in the middle of the book. He and Shi jump 200 years into the future, everyone from the first half dies, and Luo emerges into a completely different world and advanced work.
What this series does well is put human generations in perspective. Xiu paints a vivid picture of humans in a wave pool. The water behind the wave is the deceased ancestor, the water in front is the descendants not yet born. The action of the series follows the humans, alive, in the middle of the wave as it moves through time. At the end of the pool is a wall where the wave’s fate intersect with the Trisolarian fleet.
Where Three Body Problem tapped into something deep about scientific discovery and technological progress, Dark Forest drills into those tools’ application: species level survival. It’s the first axiom of Luo’s cosmic sociology and it underpins his solution to Fermi’s Paradox. Xiu imagines the universe as a “Dark Forest” filled with hunter-like civilizations stalking one another, killing each other silently, lest their position be revealed and they too be exterminated. It’s bleak and is revealed slowly at first — then epically at the book’s conclusion.
My small gripe is with the sophons that were in both this and The Three Body Problem. While they’re a great plot device for instantaneous communication and a halt on human technology, they confound Luo/Xiu’s solution to Fermi’s paradox. The Trisolar planet produced many sophons within a short time and shot them to Earth at the speed of light. If they’re so cheap and powerful, civilizations of the dark forest could monitor virtually every Earth-like planet in their vicinity, and Luo’s destruction “spell” would not have worked as easily as it did on his targeted star.