It's about 50 pages long. Kind of hard to cliff that.
But here's the summary on Wikipedia:
Industrial Society and Its Future begins with Kaczynski's assertion that "[t]he
Industrial Revolution and its consequences have been a disaster for the human race."
Kaczynski states that technology has had a destabilizing effect on society, has made life unfulfilling and has caused widespread psychological suffering. He argues that because of technological advances, most people spend their time engaged in useless pursuits which he calls "surrogate activities", wherein people strive towards artificial goals, such as scientific work, consuming mass entertainment, following sports teams, etc. He predicts that further advances in technology will ultimately result in "extensive genetic engineering of human beings, so that man in the future will no longer be a creation of nature, or of chance or of God," and that "social systems will not be adjusted to suit the needs of human beings. Instead, human beings will be adjusted to suit the needs of the system." He states that "[m]any people understand something of what technological progress is doing to us yet take a passive attitude towards it because they think it is inevitable. But we don't think it is inevitable. We think it can be stopped."
Kaczynski argues that erosion of human freedom is a natural product of industrial society because "[t]he system has to regulate human behavior closely in order to function," and that reform of the system is impossible as "[c]hanges large enough to make a lasting difference in favor of freedom would not be initiated because it would be realized that they would gravely disrupt the system." However, he states that the system has not yet fully achieved "control over human behavior" and "is currently engaged in a desperate struggle to overcome certain problems that threaten its survival." He predicts that "if the system succeeds in acquiring sufficient control over human behavior quickly enough, it will probably survive. Otherwise it will break down," and that "the issue will most likely be resolved within the next several decades, say 40 to 100 years." Kaczynski therefore states that the task of those who oppose industrial society is to promote "social stress and instability," and to propagate "an ideology that opposes technology," one that offers the "counter-ideal" of nature "in order to gain enthusiastic support." Thus, when "the system becomes sufficiently stressed and unstable, a revolution against technology may be possible."
Throughout the document, Kaczynski addresses
leftism as a movement. He defines leftists as "mainly socialists, collectivists, 'politically correct' types, feminists, gay and disability activists, animal rights activists and the like," states that leftism is driven primarily by "feelings of inferiority" and "oversocialization," and derides leftism as "one of the most widespread manifestations of the craziness of our world." Kaczynski additionally states that "a movement that exalts nature and opposes technology must take a resolutely anti-leftist stance and must avoid all collaboration with leftists", as in his view "[l]eftism is in the long run inconsistent with wild nature, with human freedom and with the elimination of modern technology". He also criticizes
conservatives, describing them as "fools" who "whine about the decay of traditional values, yet they enthusiastically support technological progress and economic growth. Apparently it never occurs to them that you can't make rapid, drastic changes in the technology and the economy of a society without causing rapid changes in all other aspects of the society as well, and that such rapid changes inevitably break down traditional values."