The Dark Forest

The Dark Forest (Chinese: 黑暗森林, pinyin: Hēi'àn sēnlín) is a 2008 science fiction novel by the Chinese writer Liu Cixin It is the second book in Three Body Problem (trilogy). The English version, translated by Joel Martinsen, was published in 2015.

Plot
The UN forms the Planetary Defense Council (PDC) to coordinate defensive efforts against the impending assault of the Trisolarans, whose fleet is 421 years away. However, the subatomic computers sent from Trisolaris, known as sophons, have already reached the Earth, and are able to conduct surveillance of national secrets and private conversations, and to disrupt the operation of particle accelerators, the latter serving to obstruct any new discoveries in physics. Since the sophons cannot read minds, the PDC decides that, in addition to regular military expansion, there will be four people appointed as Wallfacers, to be granted access to the resources of the UN to develop grand strategies known only to themselves. Three of them are chosen on the basis of merit: Frederick Tyler, former secretary of defense of the USA; Manuel Rey Diaz, former president of Venezuela, also a nuclear engineer; and Bill Hines, former president of the EU, also a neuroscientist. To general surprise, the fourth Wallfacer is announced to be Luo Ji, an obscure Chinese professor of sociology who is lazy and un-ambitious. Later it is revealed that Luo was chosen because ETO assassinate him. Tyler designs a swarm of small, nuclear-equipped Kamikaze space-fighters, but his secret plan to work with the ETO to double-cross Earth's forces, and subsequently to triple-cross the Trisolarans, is published by his Wallbreaker. The nations of the world denounce him as a war criminal, driving him to suicide. Diaz requests funding for massive nuclear warheads, and has one successfully detonated on Mercury, but his secret plan is exposed by his own Wallbreaker, namely, to build a nuclear mechanism which can propel Mercury into the sun, leading the sun to explode and consume the rest of the solar system. At the next PDC hearing, the USA decides to violate Diaz's diplomatic immunity and arrest him, but Diaz escapes by pretending that he holds a dead man's switch which can destroy NYC. Upon returning to Venezuela, he is reviled by the populace as a war-criminal, and killed by an angry mob. Hines conducts experiments to amplify intelligence, in the process discovering a means of implanting beliefs. The UN allows soldiers to use Hines's device to implant faith in victory against Trisolaris, as a controversial means of curbing Defeatism, but the program is later terminated, being seen as a crime against humanity. Luo refuses to work, and uses his funding to live a comfortable life, and to find an ideal woman to marry. However, he comes to realize some truths about galactic civilizations based on a conversation which he had many years ago with his former teacher, Ye Wenjie, who was later imprisoned for founding the ETO. Accordingly, Luo arranges for the location of a star 50 light-years away to be broadcast throughout the galaxy, using the sun as an amplifier. Both Luo and Hines enter hibernation. Around this time, an observatory notices through the tracking of space dust that the Trisolaran fleet has launched swift probes that will reach Earth in merely 200 years.

Luo, Hines, and the wife of Hines wake up 200 years later to a wealthier and more advanced society, albeit without improvement in particle-physics and supercomputing due to the ongoing sophon sabotage. The Earth now has thousands of spaceships which are both larger and faster than Trisolaris' one thousand ships. The ETO has been eliminated. The UN is confident of its victory, and writes off the old Wallfacer project as an absurdity. The wife of Hines reveals that she was the last Wallbreaker, and exposes the secret part of Hines's plan: the belief implanting device was inverted, causing its subjects to believe victory was impossible, and to conspire to escape the Earth. The human space fleet, worried that the device may have produced a secret society of escape advocates, brings Zhang out of hibernation to investigate. Zhang seizes the moment to sedate the largest ship's crew, and drive the ship out of the solar system, having been a secret Defeatist all this time. The space-fleet sends four ships after Zhang. Meanwhile, the first Trisolaran probe passes Jupiter, and in a show of strength, humanity launches 2,000 warships to intercept it. However, the probe is revealed to be a bullet made of "strong interaction" material. It pierces through the fuel-cells of the ships, destroying all but two. These two decide to escape the solar system rather than reporting back to base. Hearing the news, society devolves into hysteria. The four ships which were chasing Zhang decide to join his desertion. However, each ship eventually concludes that it can maximize its chances of survival by killing the crews of the other ships and harvesting their resources. The five ships try to kill each other, with one emerging victorious. On the other side of the solar system, one of the two escaping ships also kills the other. Luo explains how these events confirm his earlier theory: there is life everywhere in the galaxy, but owing to exponential growth and limited resources, the incentive is very high for each galactic civilization to preemptively kill any others. The only thing stopping this is the lack of knowledge of others' locations. Luo is made a Wallfacer again after the UN notices that the star earlier marked by Luo has been destroyed. His strategy has been to force Trisolaris into a truce by threatening to broadcast their location. However, the Trisolarans prevent this by using the probe to blanket Earth in EMF waves. Luo seemingly gives up, and joins the government's Snow Project, a futile effort to use nuclear bombs to create vast clouds of debris, as a way of tracking the remaining journey of Trisolaris's fleet. He is shunned by the public for not having a plan to defeat Trisolaris, and descends into alcoholism. However, it is revealed that he has encoded a message into the bombs: upon their explosion, the resulting precisely-placed dust clouds will cause the sun to appear to flicker to an extra-solar observer, thereby relaying Trisolaris's location to the galaxy in a type of Morse code. Trisolaris is forced to agree to a truce with Earth. The government approves of Luo's work and agrees to bring his wife and daughter out of hibernation, whereupon they are reunited.

Character
Ye Wenjie(叶文洁) – Astrophysicist who initiated initial contact between Earth and Trisolaris. Spiritual leader of the Earth Trisolaris Organisation.

Mike Evans(麦克·伊文斯) – ETO financial backer and key leader, killed in previous book.

Chang Weisi (常伟思) – General in the PLA and Zhang Beihai co-worker. First commander of humanity's space force and a defeatist who envies Zhang's Triumphalism.

Zhang Beihai(章北海) – Political commissar in the PLA Navy. Assassinates proponents of media-drive research in order to guarantee the development of plasma drives.

Shi Qiang (史强), also nicknamed Da Shi (大史) – Wallfacer Head of Security.

Wu Yue (吴岳) – Captain in the PLA Navy

Zhuang Yan (庄颜) – Graduate of the Central Academy of Fine Arts, Luo Ji's wife

Ding Yi(丁仪) – Theoretical physicist

Secretary General Say: Secretarial General of the United Nations.

Dongfang Yanxu (东方延绪) – Captain of space warship Natural Selection.

Kent (坎特) – Wallfacer Security Staff for Luo Ji. Despite best efforts at physically securing Luo Ji in an underground bunker, passes on Bed Flu bioweapon to Luo Ji. Dies of old age on Luo Ji's estate.

Wallfacers (面壁者):

Frederick Tyler (弗雷德里克·泰勒) - Former US Secretary of Defense.

Manuel Rey Diaz (曼努尔·雷迪亚兹) – Former President of Venezuela.

Bill Hines (比尔·希恩斯) – English neuroscientist and former president of the EU.

Luo Ji (罗辑) – Astronomer and sociologist. Given the initial axioms of Dark Forest theory by Ye Wenjie. Is his own Wallbreaker when he concludes that the axioms result in the Dark Forest state of the universe, and thus the only strategic option against the Trisolarians is mutually assured destruction through broadcast of their interstellar coordinates.

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