The impact of the mechanics’ institute library movement is investigated, providing an opportunity to identify the impact these libraries had on a predominately working-class adult readership both before and after the passing of the Public Libraries Act in 1850. In particular, the impact that the Yorkshire Union of Mechanics’ Institutes had on the library movement is explored. The contention made before the Select Committee on Public Libraries in 1849 that ‘for the last many years in England everybody has been educating the people, but they have forgotten to find them any books’ is reassessed. In addition, the view held by some education historians that mechanics’ institutes were ‘frivolous and their libraries were only used for fiction’ is challenged.