Listening to Cixin Liu’s THREE-BODY trilogy reminds me of those graphics on cosmology that illustrate our relative scale in the universe. It starts with the microscopic world of individual atoms and molecules (or even subatomic particles like quarks and neutrinos), expands outward to individual cells, organisms, and larger creatures, then jumps out further to continents and the planet Earth, zooming back to encompass our solar system, the Milky Way galaxy, and then pulling out further to an endless sea of galaxies that make up our universe. But Liu doesn’t stop there. He’s just gotten started, really. After all, there are more universes out there, and we’ve only mentioned three dimensions so far.
The first book, The Three-Body Problem, focused mainly on the Earth and communications with the first alien race encountered by humanity, the Trisolarans. This book featured ‘sophons,’ protons unfolded into two dimensions and then etched with circuitry via mesons, creating super-powerful computers that occupy almost no space in three dimensions, allowing them to spy on human activities and interfere with scientific development.
The second book, The Dark Forest, introduced a new phase in Earth-Trisolaran relations, the Crisis Era, in which humanity had 400 years to prepare for an invasion by the Trisolarans after being coldly told “You’re bugs.” Humanity reacted in various ways, with some treating the Trisolarans as vengeful gods or saviors of mankind, or descending into hedonism and despair, but the most important project is the Wallfacer Project, in which the Planetary Defense Council selects four important individuals with the power to formulate different strategies to handle the impending invasion.
The catch is that the Trisolarans can monitor every move of humanity, so the only way to defeat them is to use subterfuge, trickery, and misdirection. It’s a very unusual take on the alien invasion theme, and the concept of a Wallfacer is one more familiar to Chinese readers, who recognize it from classic Chinese literature. The final part of the book has a climactic encounter between the human and Trisolaran fleets, and the brilliant stratagem that Luo Ji uses to prevent humanity’s annihilation by the enemy.
The third book, Death’s End, begins by detailing the birth of the Staircase project, another response to the Tri-Solaran Crisis. It introduces the main character of the book, Cheng Xin, a highly intelligent young female aerospace engineer. Despite her lack of experience, her innovative ideas about creating propulsion systems that approach light speed gain the attention of her superiors. When the project head demands lighter payloads to launch an individual human envoy toward the approaching Trisolaran fleet, she comes up with an innovation that will require the ultimate sacrifice, and finds the perfect person for the mission.
Thanks to Luo Ji’s genius, humanity and the Trisolarans have entered a stalemate known as the Deterrence Era. Luo Ji is the Swordbearer, ready to push a button that will almost certainly lead to the destruction of both Earth and Trisolaris at the hands of unseen but powerful aliens by revealing the locations of Earth and Trisolaris to the galaxy. This is an extension of the Dark Forest concept, which likens the universe to a dark forest filled with different species. Nobody knows if the others are hostile, but if they naively assume they are friendly they will likely be destroyed first, so the only logical response from a game-theory perspective is to strike first and destroy your opponent, whether they appear friendly or hostile. It is an interesting metaphor for the Cold War on a galactic scale, and a pessimistic solution to Fermi’s Paradox.
Eventually, as Luo Ji gets too old to remain the Swordbearer, it is decided that Cheng Xin will take over his duties. To reveal the following events would constitute major spoilers, but suffice to say that the Deterrence Era rapidly transitions to the Broadcast Era and then the Bunker Era due to a series of dramatic double-crosses, brinksmanship, and momentous decisions. This portion of Death’s End is very exciting and fast-paced, fulfilling the build-up of the first third of the book.
The Bunker Era makes up the bulk of the remaining half of Death’s End. Humanity remains under constant threat of destruction at the hands of unseen, more advanced species, the proverbial “Dark Forest Strike.” So they take refuge behind the larger planets of the solar system, in case a strike targeting the sun destroys it and the surrounding planets. But there are other factions that would prefer a different approach, such as the “Black Domain” strategy of using black holes to slow down the speed of light in the solar system, thereby blocking external strikes but isolating humanity from the rest of the galaxy. There is also the “Curvature-Propulsion” strategy, which seeks to create light-speed capable ships by manipulating the curvature of space. However, those that wish to avoid the attention of other alien species are concerned that light-speed ships will invite a “Dark Forest Strike.” So once again humanity struggles with itself, facing choices that may determine the survival of the species.
The final portion of Death’s End has so many mind-boggling set-pieces and events that describing them will certainly ruin your enjoyment of the book. Liu’s descriptions of multi-dimensional space and massive galactic events are incredible and even beautiful at times, as is the translation job done by Ken Liu. Kudos also go to the audiobook narrator P.J. Ochlan, who gives the characters the requisite attention amid the events that threaten to engulf them. The Dark Forest concept takes front and center in the closing movements, as we finally see humanity from the perspective of aliens so advanced that we indeed seem little more than bugs. What those aliens have in store for humanity is stunning, humbling, and deeply tragic.
Which brings us to the Galactic Era, as the remnants of humanity learn exactly where they stand in the galactic pecking order (hint: pretty far down, in case you didn’t guess already). The characters theorize what the most advanced alien races are like, and what their plans for the universe are, including multi-dimensional warfare, trying to outlive the heat-death of the universe, creating mini-universes outside of time, and the Big Crunch that awaits all sentient life at the end. It’s mind-expanding and terrifying in its implications.
In my interview with Cixin Liu after the publishing of The Dark Forest, he indicated that his favorite SF authors include Arthur C. Clarke, Ray Bradbury, and Jules Verne, and their influence can be clearly seen, especially Clarke. He is also deeply influenced by George Orwell’s Nineteen Eighty-Four, and the dark tone of much of the THREE-BODY trilogy is certainly dystopian, in a galactic sense, though there are elements of hope in the ending of Death’s End and the story centers on the heroes that valiantly strive to save humanity. The overwhelming impression is not of a cold, uncaring universe, but rather an actively-hostile one in which humanity are indeed bugs scurrying across the floor, hoping to avoid getting stomped on.