This paper traces the origin, prevalence, and eventual decline of libraries for the semi-skilled working populations of some major industrial centers in the Northeastern United States and the United Kingdom. Mechanics’ Institutes provided a third space away from the home, work and the pub and as such represented an ideal space for the nineteenth-century liberal ethos of self-help and self-reliance. The proprietors and members of these institutes demonstrated these ethics though their collections and library events held in the institutes. While much has been written about the foundations and purposes of mechanics’ institutes, little has been written about the social and political environment surrounding these seemingly philanthropic and well-meaning institutions. Although some authors have depicted mechanics’ institutes as instruments of temperance, little has been written about their role as purveyors of the political ideologies of self-help, self-reliance, individualism, or expansionism. Mechanics’ institutes have a dual role as both libraries of the semi-skilled and unskilled labor force as well as elite social libraries charging membership dues and lecture fees. It is appropriate, therefore, to portray their existence in the context of the social history of urban centers and in the history of the social library movement before 1876, when the American Library Association was established and the public library movement gained momentum.