You’ve probably seen the black and white police sketch of a man with a mustache, wearing dark aviators and a hoodie, a patch of curly hair peaking out from underneath. That ominous image tormented Americans for years, because the man behind those sunglasses was responsible for a string of terrorist attacks that killed three people and maimed dozens more from 1978 to 1995. You’ve probably also heard about how this man—known only as the Unabomber—sent increasingly sophisticated bombs to unsuspecting victims in the science, technology and airline industries. Some sustained minor injuries and others suffered shrapnel wounds and severe burns,...