Theodore Kaczynski, better known as the Unabomber, is one of America's most infamous domestic terrorists. His 1995 Manifesto, 'Industrial Society and Its Future', is well known and influential among radicals of many stripes, yet surprisingly little has been written about it. This article uncovers the origins of Kaczynski's ideas and examines his influence on contemporary anti-tech radicalism. Using newly discovered archival material, I reveal the sources that Kaczynski deliberately concealed in the 1995 Washington Post version of his Manifesto. My excavation of his sources shows that his ideology is more novel than the common 'eco-terrorist', 'green anarchist', and 'neo-Luddite' labels suggest. His Manifesto is a synthesis of ideas from three well known academics: French philosopher Jacques Ellul, British zoologist Desmond Morris, and American psychologist Martin Seligman. Further, I show that it is necessary to understand Kaczynski's distinct combination of ideas in order to understand the anti-tech radical groups that he has inspired, such as the Mexican terrorist group Individualidades Tendiendo a lo Salvaje (ITS). The ideological novelty of anti-tech radicalism has been overlooked because, like Kaczynski himself, it has been mistaken for radical environmentalism or green anarchism.