This article traces a brief history of a particularly relevant concept in political economy and economic sociology: technological unemployment. The historical narration aims at covering four centuries, since the beginning of the industrial revolution up to the present. As a consequence, it has to be highly selective. It is mainly based on sources in the English language and refers only to a few of the many social scientists involved in the debate. The scopes of the inquiry are essentially two. The first is to show that focusing on technological unemployment as an idea - and not simply as a phenomenon - is appropriate, because of the high level of controversy that still characterizes the debate. The second is to drive attention to a concept that could be extremely useful to understand the technological and societal changes occurring in the twenty-first century.