This essay is about possible causes to the female dominance in public libraries. We have focused on the 20th century in Sweden and the development of public libraries during this time. For this purpose we have done a survey of three different cities, Uppsala, Jönköping and Skara, during three different years, 1938, 1958 and 1978. We have studied salaries, gender and titles for the employed at the head library in each city and then made comparisons between them. In conjunction, we have also studied how women were looked upon by the rest of society, regarding their education and work opportunities. To achieve a comprehension of the society's view of women we have, in the essay, put three different theories of the so called "female nature" in center. The genderization in the labour market has also been set to discussion. A comparison between librarians, teachers at different levels, and postoffice employees, has also been made regarding their salaries during the years (1938, 1958 and 1978).