The Dark Forest is Cixin Liu’s sequel to The Three Body Problem and the second book of The Remembrance of Earth's Past Trilogy. My commentary on the first novel is here.
Taking place in the years following The Three Body Problem, this book concerns itself with the coming alien invasion of Earth. The Trisolaran fleet is 450 years away from reaching the solar system. However, the governments of Earth, working together to deal with the threat, have serious problems. First, The ETO is an organization of humans who are working to assist the aliens. Second, the Trisolarans have managed to send subatomic particles called sophons to Earth ahead of the invasion force. Sophons are basically protons containing supercomputers. They are capable of shutting down all of humanity’s research into particle physics, thus stopping human technological progress at a certain point. This puts a limit on propulsion, weapons and computer technical advancement and means that humans will be unprepared to meet the Trisolaran fleet in the future. The sophons are also capable of spying on humans anywhere, thus allowing the aliens to know everything the humans are doing in their attempts to thwart the invasion.
In response, the governments of the world appoint individuals known as Wallfacers. The Wallfacers are people who are given unprecedented authority to coordinate resistance to the invasion. The Wallfacers work alone and do not communicate their plans to others, as the sophons can eavesdrop on all communications and conversations. Thus, the Wallfacers plan alone, and they are expected to use subterfuge and work on massive diversions in order to hide their strategies from the Trisolarans.
Luo Ji is the main character in the book and a Wallfacer. Other Wallfacers include: Bill Hines, a former president of the European Union and a brilliant neuroscientst who plans to enhance and manipulate human intelligence to fight the Trisolarans; Frederick Tyler, a former American secretary of defense, who plans to fight the Trisolarans with a fleet of tiny spaceships; Manuel Rey Diaz, the former president of Venezuela, who plans to build massive nuclear weapons that can send planets off of their orbits to use in opposing the aliens.
There are many additional characters, including various members of humanity’s new space fleet. Zhang Beihai is a naval officer who joins the new space fleet and becomes instrumental in its development. Shi Qiang, the rough-around-the-edges detective from The Three Body Problem, is back. He plays a major part as Luo Ji’s protector.
Luo Ji is a fascinating character. Initially, he is chosen as a Wallfacer for inexplicable reasons. He is a mediocre scientist, a womanizer, he is corrupt and hedonistic. He initially tries to refuse the role. When refusal fails, he uses his position to live a life of luxury and excess and does nothing to formulate plans against the Trisolarans. Luo Ji’s behavior is initially taken for a ruse meant to fool the aliens into believing that he is doing nothing while really formulating plans against them. When authorities realize that he is actually just milking the system, they use coercion on him. This prompts him to take action that becomes a true threat to the Trisolarans who, it turns out, have always feared his potential.
As the plot advances, the various plans of the Wallfacers develop along with counter plans of the ETO and the aliens. Later on in the story, many of the main characters go into suspended animation to oversee the plans as they advance over the course of centuries. The depiction of Earth’s future is imaginative and intelligent. Eventually, the humans face a Trisolaran probe that enters the solar system. Everything comes to a head as an enormous fleet of Earth’s spaceships goes to confront it.
This is a serious work of science fiction. Though some of the science seems farfetched, it is mostly based upon real principles. While things like sophons probably could not exist in real life, they are based upon actual theories and at least educated speculation. Future depictions of advances in suspended animation and spaceflight are depicted in scientific literate ways.
There are also references in this book to various science-fiction novels and films, including works by Isaac Asimov and Author C. Clarke. There are references to the writings of Carl Sagan. The plot and themes are also reminiscent of the works of these and other writers. This book, like The Three Body Problem, is a treat for fans of older science fiction as well as those who are interested in science and technology.
There are strong humanistic and positive themes here. As the plot unfolds, it becomes apparent that the universe is filled with advanced civilizations. Due to the need to survive and compete for resources, civilizations are quick to destroy other civilizations in order to eliminate threats and competition. Hence, the “Dark Forest” of the title. The dark nature of the universe is further illustrated when several Earth starships begin a joint, multi-generation journey out into the galaxy in order to escape the alien invasion. Crews of two of the ships murder the crews of the other ships in order to obtain fuel and spare parts. These actions are presented as the only possible way that the ships will be able to reach their destinations. The picture of a very bleak universe and existence is painted here.
However, better tendencies of intelligent life begin to shine through. At one point, a Trisolaran who has attempted to save humanity from destruction speaks to Luo Ji about a future universe that is based upon love as opposed to genocidal survival of the fittest.
“I only wish to discuss with you one possibility: Perhaps seeds of love are present in other places in the universe. We ought to encourage them to sprout and grow.”
Luo Ji replies,
"“That’s a goal worth taking risks for…I have a dream that one day brilliant sunlight will illuminate the dark forest.”
The sun was setting. Now only its tip was exposed beyond the distant mountains, as if the mountaintop was inset with a dazzling gemstone. Like the grass, the child running in the distance was bathed in the golden sunset."
The above seems to encapsulate what are ultimately positive motifs embodied in this novel."
There are also anti-totalitarian themes contained here. As the narrative takes place over centuries, long term trends in human history are fair game for the author. Both right wing and left wing totalitarian regimes and solutions are shown to be harmful to humanity. Collectivization under strong governments is initially tried on a worldwide basis in order to mobilize human society against the aliens. This leads to catastrophe. Famine and social decay are the result. Eventually, a more open system brings world prosperity and a real chance to oppose the Trisolarans.
I am always hesitant to label a sequel superior to the original. However, as compared to The Three Body Problem, this book has a more interesting plot, more focused themes and more nuanced characters. I think that this novel is better. With that, it may make more sense to consider The Three Body Problem and this book as one work. The first book ended without a resolution to the alien invasion threat. Though this book is the second in a trilogy, this novel seems to have wrapped up the entire story very neatly. In a way, these two works together make up a single, strong science-fiction story that is worthwhile reading for fans of the genre. This work really does not work as a standalone. It only makes sense as a follow up to The Three Body Problem.
In terms of plot, technology and science, it is a superb book. The characters are interesting and some show complexity. As I mention above, I think that readers of the first book would do well to continue on to this one. I have one more book, Death's End, in the series to go. I am very much looking forward to it.